5 Animal Species With Surprising Memories

A repost of an original article from The Scorpion and the Frog.

We often think of animals as having hilariously short memories – the “memory of a goldfish”, if you will. But many animals have memories that can put yours to shame.

There are many different kinds of memory and each of them is controlled differently by different parts of the brain. Short-term memory can be thought of as the brain’s scratch pad: It holds a small amount of information for a short period of time while your brain decides whether it is worth retaining in long-term memory or if it can just fade away. When a short-term memory becomes a long-term memory, this process is called consolidation and involves physiological changes in the brain.

Long-term memory can be further divided into two main types: procedural memory and declarative memory. Procedural memory is used to remember how to do things and what objects are needed to do those things. Declarative memory is used for recall and can be further divided into memory used to recall facts (semantic memory) and events (episodic memory).Each of these different types of memories are stored in different parts of the brain. Furthermore, different types of facts (remembering faces versus numbers, for example) and different types of events (depending on if they have an emotional component or not, for example) are also stored in the brain differently. Because species differ in how we rely on our brains, it makes sense that this might be reflected in our abilities to remember in different ways.

So let’s check out some of the most amazing memories in the animal kingdom:

Do you know what all your kids and nieces and nephews are
doing right now? These elephants do. Photo by PJ KAPDostie
at Wikimedia.

1) They say an elephant never forgets. Elephants are very social animals that live in large stable herds. This has led to some incredible feats of social memory. They can keep track of the whereabouts of 30 group members at once and they can remember an animal they briefly met over 20 years ago. For an animal that lives about 50 or 60 years, this is very impressive. Elephants also have outstanding episodic memory: In 1993, Tarangire National Park in Tanzania suffered the worst drought that it had seen in 35 years. It was so severe that it killed 20% of elephant calves, compared to the average loss of about 2%. Of three herds that lived in the park in 1993, two of them were led by females that had lived during the severe droughts of 1958-61 and those herds left the park and were more successful at finding food and water. The herd that stayed was led by a younger female that had never experienced such a severe drought and that herd suffered 63% of the total mortality.

Dolphins never forget a name. Photo from the
NOAA Photo Library available at Wikimedia.

2) Bottlenose dolphins have even more incredible social memories. They, like elephants, live in complex social groups. Each dolphin has a unique whistle that it uses like a name. When they are played recordings of whistles of companions they lived with years or even decades earlier, they approach the speakers for longer than when they are played the whistles of dolphins they never met. The fact that they, like elephants, remember companions for over 20 years is much more impressive because their lifespan is only 40-50 years!

Sea lions can remember
meaningless tricks for years.
Photo by LSA2886 at Wikimedia.

3) Sea lions have amazing procedural memory. In 1991, marine biologists at the University of California, Santa Cruz, taught a California sea lion named Rio a card trick. They held up one card with a letter or number on it and another set of two cards: one that matched the first card and one that did not. Rio learned to pick the matching card to be rewarded with a fish. Everyone was impressed and she didn't do the trick again... until 10 years later, when researchers pulled out the cards and asked her to do it again. Rio had the same score in 2001 with no practice that she did in 1991 when she originally learned the trick!

Clark's nutcrackers can remember where they stashed
30,000 pine nuts.I can't even keep track of my keys.
Photo by Gunnsteinn Jonsson at Wikimedia.

4) Clark’s nutcrackers can remember the exact location of 30,000 pine nuts. This kind of superhero ability is born out of necessity: nutcrackers completely rely on their caches of food to get them through the winter. However, despite their amazing long-term spatial memory, their short-term memory is below average: they can’t even remember the color of a light for 30 seconds.

5) Chimpanzees can put your working memory to shame. Working memory is a form of short-term memory that is applied to a task. A group of researchers taught chimpanzees to do a task in which they were shown the numbers from 1-9 in random locations on a computer screen. When the numbers are covered, chimps can remember where each number was. Furthermore, they only need to see these randomly placed number for a few seconds to get this task correct. In comparison, only people that are considered savants have comparable abilities.

Hey Hey! We’re The Monkeys!

 Updated and reposted from March 6, 2013.

A tamarin rock star
(photographed by Ltshears at Wikimedia)

Our moods change when we hear music, but not all music affects us the same way. Slow, soft, higher-pitched, melodic songs soothe us; upbeat classical music makes us more alert and active; and fast, harsh, lower-pitched, dissonant music can rev us up and stress us out. Why would certain sounds affect us in specific emotional ways? One possibility is because of an overlap between how we perceive music and how we perceive human voice. Across human languages, people talk to their babies in slower, softer, higher-pitched voices than they speak to adults. And when we’re angry, we belt out low-pitched growly tones. The specific vocal attributes that we use in different emotional contexts are specific to our species… So what makes us so egocentric to think that other species might respond to our music in the same ways that we do?

A serene tamarin ponders where he placed
his smoking jacket (photographed by
Michael Gäbler at Wikimedia)

Chuck Snowdon, a psychologist and animal behaviorist at the University of Wisconsin in Madison, and David Teie, a musician at the University of Maryland in College Park, teamed up to ask whether animals might respond more strongly to music if it were made specifically for them.

Cotton-top tamarins are squirrel-sized monkeys from northern Colombia that are highly social and vocal. As in humans (and pretty much every other vocalizing species studied), they tend to make higher-pitched tonal sounds when in friendly states and lower-pitched growly sounds when in aggressive states. But tamarin vocalizations have different tempos and pitch ranges than our tempos and pitch ranges.

Chuck and David musically analyzed recorded tamarin calls to determine the common attributes of the sounds they make when they are feeling friendly or when they are aggressive or fearful. Then they composed music based on these attributes, essentially creating tamarin happy-music and tamarin death metal. They also composed original music based on human vocal attributes. They played 30-second clips of these different music types to pairs of tamarins and measured their behavior while the song was being played and for the first 5 minutes after it had finished. They compared these behavioral measures to the tamarins’ behavior during baseline periods (time periods not associated with the music sessions).

As the researchers had predicted, tamarins were much more affected by tamarin music than by human music. Happy tamarin music seemed to calm them, causing the tamarins to move less and eat and drink more in the 5 minutes after the music stopped. Compared to the happy tamarin music, the aggressive tamarin music seemed to stress them out, causing the tamarins to move more and show more anxious behaviors (like bristling their fur and peeing) after the music stopped.

The tamarins also showed lesser reactions to the human music. They showed less anxious behavior after the happy human music played and moved less after the aggressive human music played. So, human voice-based music also affected the tamarins to some degree, but not as strongly. This may be because there are some aspects of how we communicate emotions with our voice that are the same in tamarins.

Can you imagine what we could do with this idea of species-specific music? Well, David and Chuck did! They have since developed music for cats using similar techniques.

We often think of vocal signals conveying messages in particular sounds, like words and sentences. But calls seem to do much more than that, making the emotions and behaviors of those listening resemble the emotions of those calling.

Want to know more? Check these out:

Snowdon, C., & Teie, D. (2009). Affective responses in tamarins elicited by species-specific music Biology Letters, 6 (1), 30-32 DOI: 10.1098/rsbl.2009.0593

Snowdon, C., Teie, D. and Savage, M. (2015). Cats prefer species-appropriate music. Applied Animal Behaviour Science, 166, 106-111.

Friends Without Benefits: A Guest Post

A reposting of an original article by Joseph McDonald

Do you want to avoid the friend zone?
Photo by freedigitalphotos.net.

Guys DREAD the friend zone. That heart-aching moment when the girl you’ve been fawning over for years says you’re the best listener, the sister she never had, or so much better than a diary! You’ve been so nice to her and her friends, listening to all their drama. But that’s just the problem... you’re too nice to too many people.

Research performed by Aaron Lukaszewski and Jim Roney at the University of California – Santa Barbara (UCSB) tested whether preferences for personality traits were dependent on who the target was. In Experiment 1, they asked UCSB undergrads, on a scale from 1 to 7, the degree to which their ideal partner would display certain traits towards them and towards others. These traits included synonyms for kindness (e.g. affectionate, considerate, generous, etc.), trustworthiness (committed, dependable, devoted, etc.), and dominance (aggressive, brave, bold, etc.). Experiment 2 replicated the procedures of Experiment 1. The only difference was that the term “others” was divided into subsets including unspecified, family/friends, opposite sex non-family/friend, and same-sex non-family/friend.

Let’s go over the do’s and don’ts so that future “nice guys” aren’t friend zoned. According to the findings, as graphed below:

Figure from Aaron and Jim's 2010 Evolution and Human Behavior paper.

1. Women generally prefer men who are kind and trustworthy. So, to get that girl, don’t be mean; that’s not the point. This isn’t 3rd grade so don’t pull her hair and expect her to know that you LIKE-like her.

2. Women prefer men who are kinder and more trustworthy towards them than anyone else. So it’s not so much whether you are nice enough, its whether she knows you are nicer to her than anyone else.

3. Women prefer men who display similar amounts of dominance as they do kindness. Dominance isn’t a bad thing, as long as you can distinguish her friends from her foes; especially her male friends.

4. To make things more complicated, women also prefer men who are directly dominant toward other men but don’t display dominance toward them or their family/friends, whether male or female. Some guys may want to befriend these other men, but be weary. Women preferred dominance over kindness in this situation, so kindness may not be enough.

These preferences may have developed to avoid mating with someone willing to expend physical and material resources for extramarital relationships, and invest greater in her and the children. Moderate kindness and trustworthiness toward others will maintain social relationships and prevent detrimental relationships, which may be why women generally prefer kind and trustworthy guys. But in all fairness, women can be in the friend zone too; just look at Deenah and Vinny (excuse the shameful Jersey Shore reference).

There are some things that guys look for in a mate, so ladies, here is a little advice:

1. Guys generally want a mate who is kind and trustworthy, too. We’re not that different; so don’t act a little crazy because you think he likes it. He doesn’t.

2. Guys also prefer women who display dominance toward other women (non- family/friend). Don’t be afraid to put that random girl with the prying eyes in her place.

Contrary to the hypotheses predicting female mate preferences, male mate preferences may have developed as a way to take advantage of strong female-based social hierarchies. No matter what the reasoning, however, if you can
1) be kinder and more trustworthy towards that special someone than anyone else and
2) display dominance over other same-sex people, then feel free to say good-bye to the friend zone!


For further details, check out the original experiment:

Lukaszewski, A., & Roney, J. (2010). Kind toward whom? Mate preferences for personality traits are target specific Evolution and Human Behavior, 31 (1), 29-38 DOI: 10.1016/j.evolhumbehav.2009.06.008

Caught in My Web: We Are Primates

Image by Luc Viatour at Wikimedia Commons

If the news cycle these days has you wondering about our own humanity, take a moment to reflect on our primate nature. For this edition of Caught in My Web, let's explore primate behavior in the news.

1. Elizabeth Preston at Discover writes about lemur "stink flirting" in High-Ranking Male Primates Keep Wafting Their Sex Stink at Females, Who Hate It.

2. Janelle Weaver discusses how primates grant favors for their own social benefit at Nature in Monkeys Go Out on a Limb to Show Gratitude.

3. Roxanne Khamsi at NewScientist reports that Envious Monkeys Can Spot a Fair Deal.

4. Writing for The Verge, Angela Chen explains how we discovered that bonobos prefer to befriend bullies in For Bonobos, Nice Guys Finish Last.

5. In Those Lying Apes, Dale Peterson of Psychology Today discusses chimpanzee deception.

Sound familiar?

Risky Business: Ape Style

A repost of an original article from April 3, 2013.

The decisions of this chimpanzee living in the
Tchimpounga Chimpanzee Sanctuary are affected
by his social situation. Photo by Alex Rosati.

If you have a choice between a prize that is awesome half the time and totally lame the other half of the time or a mediocre prize that is a sure-thing, which would you choose? Your choice probably depends on your personality somewhat. It may also depend on your needs and your mood. And it can depend on social contexts, like if you’re competing with someone or if you’re being watched by your boss or someone you have a crush on.

All animals have to make choices. Some choices are obvious: Choose the thing that is known to be of high quality over the thing that is known to be of low quality. But usually, the qualities of some options are uncertain and choosing them can be risky. As with us, the likelihood of some primates, birds, and insects to choose riskier options over safer ones can be affected by outside influences. And we aren’t the only species to have our risk-taking choices influenced by social context.

Anthropologists Alex Rosati and Brian Hare at Duke University tested two ape species, chimpanzees and bonobos, in their willingness to choose the riskier option in different social situations. They tested chimpanzees living in the Tchimpounga Chimpanzee Sanctuary and bonobos in the Lola ya Bonobo Sanctuary, both in the Democratic Republic of Congo. Most of the apes living in these sanctuaries are confiscated from poachers that captured them from the wild for the pet trade and for bushmeat. In these sanctuaries the animals live in social groups, generally spending their days roaming large tracts of tropical forest and their nights in indoor dormitories. This lifestyle rehabilitates their bodies and minds, resulting in psychologically healthy sanctuary inhabitants.

It is in these familiar dormitories that Alex and Brian tested the apes’ propensity for making risky choices. For their experimental set-up, an experimenter sat across a table from an ape and offered them two options: an overturned bowl that always covered a treat that the apes kinda like (peanuts) versus an overturned bowl that covered either an awesome treat (banana or apple) or a lousy treat (cucumber or lettuce). In this paradigm, the peanut-bowl represents the safe choice because whenever the ape chooses it, they know they’re getting peanuts. But the other bowl is the risky choice, because half the time they get fruit (yum!), but the other half of the time they get greens (bummer).


This figure from Rosati and Hare's 2012 Animal Behavour paper shows Alex demonstrating the steps they would go through before the ape chose one of the two options.

After spending some time training the apes to be sure they understood the game, the researchers tested their choices in different social situations. In each test session, the ape was allowed to choose between the two bowls (and eat the reward) multiple times (each choice was called a trial). But before the test session began and in between choice trials, another experimenter sat with the ape for two minutes and did one of three things: In one group, the experimenter sat at the table and silently looked down (they called this the “neutral condition”). In another group, the experimenter repeatedly offered the ape a large piece of food, pulling it away and grunting whenever the ape reached for it (they called this the “competitive condition”). In a third group, the experimenter tickled and played with the ape (they called this the “play condition”).

Alex and Brian found out that whereas bonobos chose the safe option and the risky option about equally, the chimpanzees were significantly more likely to choose the risky option. But despite this species difference, both species chose the risky option more often in the “competitive condition”. Neither species increased their risk-taking in the “play condition”.

The graph on the left shows that wheras bonobos chose the safe option and the risky option each about 50% of the time (where the dashed line is), the chimpanzees chose the risky option much more often. The graph on the right shows that both species chose the risky option more often in the "competition condition" than they did in the "neutral condition". Figure from Rosati and Hare's 2012 Animal Behavour paper.

These are interesting findings, especially when you consider the natural behaviors and lifestyles of these closely related species. Bonobos can be thought of as the hippies of the ape world, happily sharing and using sex to settle disputes and strengthen relationships. In comparison, chimpanzees are more like gangsters, aggressively fighting over resources and dominance ranks. So in general, the more competitive species is more likely to take risks. But when the social environment becomes more competitive, both species up the ante. This effect doesn’t seem to be simply the result of being in a social situation, because the apes didn’t increase their risk-taking in the presence of a playful experimenter.

This still leaves us with some questions to ponder though. Are apes more likely to take risks when an experimenter is offering food and taking it away because of a heightened sense of competition, or is this the result of frustration? And would we see the same effect if the “competitor” were another ape of the same species, rather than a human experimenter? How would their behavior change if they were hungry? These questions are harder to get at, but this research does demonstrate that like in humans, the decision-making process in chimpanzees and bonobos is dependent on social context.


Want to know more? Check this out:

Rosati, A., & Hare, B. (2012). Decision making across social contexts: competition increases preferences for risk in chimpanzees and bonobos Animal Behaviour, 84 (4), 869-879 DOI: 10.1016/j.anbehav.2012.07.010

Eye Didn’t See That

By Evan Hovey

A grandmother and her grandson watching the television.
The elder is straining to see while the young man is not having any troubles.
Photo by Evan Hovey.

It’s Thanksgiving and the family just finished stuffing their faces full of turkey and cranberry fluff. Everyone meanders into the living room to sit down, let the tryptophan sink in, and watch some football. As you sit there, you start to observe the older family members around you take out their glasses or bifocals and squint towards the television in attempts to see what is going on. You begin to ponder the thought, “am I going to start to lose my eye sight as well?” Well, as it turns out, as you age, the number of cells that respond to light and color (called photoreceptors) begins to decrease.

Songhomitra Panda-Jonas, Jost Jonas, and Martha Jakobczyk-Zmija at the University of Erlangen-Nurnberg, Germany, looked into the number of photoreceptors in the retina of the eye to determine whether there was a loss as you age. The retina is the thin layer of tissue that lines the back of the eye. It is the location where your eye transfers what you see to the brain. There are two different kinds of photoreceptors in your eyes: rods and cones. Rods are those that detect light at low levels, which is what helps us see at night. Cones, on the contrary, are those that take in high light levels and help decode color. The authors believed that there would be a decrease in both kinds of photoreceptors as the eye got older (the older the person, the fewer photoreceptors). They came up with this hypothesis in part because of prior knowledge of a loss of tissue associated with vision in other parts of the eye as you age.

The researchers approached this study by obtaining fifty-five eyes from human donors that died at ages ranging from 18-85. The eyes were removed from the bodies less than eleven hours after death. Then the eyes were cut open and tissue samples from the retina were obtained. To determine the amount of photoreceptors in the tissue samples, the researchers used an ultrasound to view the retina and counted the photoreceptors on a photograph taken with the ultrasound. The two different kinds of cells were distinguished by their sizes (the larger cells were the cones and the smaller cells were the rods).

The results they found were as expected: the older you get, the fewer photoreceptors you have and the worse your eyesight is. The decline of the number of photoreceptors was at a constant rate throughout all ages of life. However, the number of rods declined faster than the number of cones. The loss of these photoreceptors causes you to view things with more difficulty. As your rods die, you begin to develop night blindness (the inability to see well in poor lighting or darkness). When your cones die, you begin to lose more of your visual perception, which includes straining when looking at something from a distance, as well as affecting how you see fine detail such as reading a book or looking at a television. The combined loss of your rods and cones is part of what causes older individuals to have more vision problems.

As you progress through life, your photoreceptors decline, causing your vision to get worse. As you sit down after Thanksgiving to enjoy some good old-fashioned fall football and the elderly people strain to see the television, you now know that the oldest person in your family is most likely having the hardest time seeing that big touchdown.


If you would like to read the actual paper, the source is located below:

Panda-Jonas, S., Jonas J., Jakobczyk-Zmija, M. (1995). Retinal photoreceptor density decreases with age: Ophthalmology, 102 (12), 1853-1859

The Best Moms in the Animal Kingdom

Moms are really important to life on Earth, as evidenced by the fact that maternal care is fairly common across the animal kingdom. In most species, females produce fewer, larger, and costlier eggs than males do sperm. Therefore, it is usually beneficial to females to maximize the possible success of each one, sometimes by gestating them inside their own bodies (as mammals do), or incubating the eggs until they are ready to hatch (as birds do), or by providing prolonged protection, food and training until they are ready to take on the world for themselves. But there is still a lot of variation in how and how much each mother gives to her offspring. Here are some of the best moms in the animal kingdom:

1. The Endurance Prize goes to orangutans: Orangutan infants cling to their moms’ bellies non-stop for the first four months of their life and they continue to completely depend on their moms for the first two years for food and transport. Their moms will continue to carry them often until they are five and will sometimes continue to breastfeed them until they are eight! After that, the young still stay close to mom, learning from her and helping her until they are sometimes in their teens.

An orangutan mama and toddler. Photo by Mistvan at Wikimedia Commons.

2. The Provider Prize goes to the crab spider, Diaea ergandros: These crab spider moms create a brood chamber and nest out of eucalyptus leaves. They guard their eggs and then spiderlings, providing protection and prey for food. These moms also make extra eggs, just for their babies to eat, and finally, they give themselves… quite literally! The babies eat their mothers completely in a rare behavior called matriphagy.

3. The Pregnancy Prize goes to elephants: Elephants are pregnant for about 22 months… nearly two years! And a baby elephant is not light to carry around… by the time it is born, it will weigh nearly 250 pounds! Just the thought of it makes me uncomfortable. So why would elephant moms need to gestate their young for such an incredibly long time? It is thought that the long gestation is needed for the proper development of their brains, so they are born with the complex cognitive and social skills needed to survive in their herd.

An African elephant family plays in the hot sun. Photo by Bernard Dupont at Wikimedia Commons.

4. The Brooding Prize goes to a deep-sea octopus: Two years is a very long time to carry a developing baby inside your body, but some animals care for their developing empryos ouside of their bodies with a behavior called brooding. Although brooding may sound easier than pregnancy, it is not for the faint of heart. A deep-sea octopus was observed brooding her eggs in the Monterey Submarine Canyon off central California for 53 months… That is nearly 4 and a half years! And that whole time she did not eat, but instead guarded and aerated the water around her precious eggs.

A deep-sea octopus. Photo by NOAA at Wikimedia Commons.

5. The Multi-Generational Prize goes to humans: Many human moms are not only good mothers, but also good grandmothers. Grandparenting is extremely rare in the animal kingdom (the first documented case of grandparenting in non-humans was as recent as 2008) and human females excel at it. They provide care, advice, resources, lessons and hugs to increase the success of their offspring and grand-offspring… It’s amazing other species haven’t picked up on this amazing secret yet!

The best moms in the animal kingdom. Photos by Sarah Jane Alger.

Risky Business: Ape Style

A reposting of an article from April, 2013

The decisions of this chimpanzee living in the
Tchimpounga Chimpanzee Sanctuary are affected
by his social situation. Photo by Alex Rosati.

If you have a choice between a prize that is awesome half the time and totally lame the other half of the time or a mediocre prize that is a sure-thing, which would you choose? Your choice probably depends on your personality somewhat. It may also depend on your needs and your mood. And it can depend on social contexts, like if you’re competing with someone or if you’re being watched by your boss or someone you have a crush on.

All animals have to make choices. Some choices are obvious: Choose the thing that is known to be of high quality over the thing that is known to be of low quality. But usually, the qualities of some options are uncertain and choosing them can be risky. As with us, the likelihood of some primates, birds, and insects to choose riskier options over safer ones can be affected by outside influences. And we aren’t the only species to have our risk-taking choices influenced by social context.

Anthropologists Alex Rosati and Brian Hare at Duke University tested two ape species, chimpanzees and bonobos, in their willingness to choose the riskier option in different social situations. They tested chimpanzees living in the Tchimpounga Chimpanzee Sanctuary and bonobos in the Lola ya Bonobo Sanctuary, both in the Democratic Republic of Congo. Most of the apes living in these sanctuaries are confiscated from poachers that captured them from the wild for the pet trade and for bushmeat. In these sanctuaries the animals live in social groups, generally spending their days roaming large tracts of tropical forest and their nights in indoor dormitories. This lifestyle rehabilitates their bodies and minds, resulting in psychologically healthy sanctuary inhabitants.

It is in these familiar dormitories that Alex and Brian tested the apes’ propensity for making risky choices. For their experimental set-up, an experimenter sat across a table from an ape and offered them two options: an overturned bowl that always covered a treat that the apes kinda like (peanuts) versus an overturned bowl that covered either an awesome treat (banana or apple) or a lousy treat (cucumber or lettuce). In this paradigm, the peanut-bowl represents the safe choice because whenever the ape chooses it, they know they’re getting peanuts. But the other bowl is the risky choice, because half the time they get fruit (yum!), but the other half of the time they get greens (bummer).


This figure from Rosati and Hare's 2012 Animal Behavour paper shows Alex
demonstrating the steps they would go through before the ape chose one of the two options.

After spending some time training the apes to be sure they understood the game, the researchers tested their choices in different social situations. In each test session, the ape was allowed to choose between the two bowls (and eat the reward) multiple times (each choice was called a trial). But before the test session began and in between choice trials, another experimenter sat with the ape for two minutes and did one of three things: In one group, the experimenter sat at the table and silently looked down (they called this the “neutral condition”). In another group, the experimenter repeatedly offered the ape a large piece of food, pulling it away and grunting whenever the ape reached for it (they called this the “competitive condition”). In a third group, the experimenter tickled and played with the ape (they called this the “play condition”).

Alex and Brian found out that whereas bonobos chose the safe option and the risky option about equally, the chimpanzees were significantly more likely to choose the risky option. But despite this species difference, both species chose the risky option more often in the “competitive condition”. Neither species increased their risk-taking in the “play condition”.

The graph on the left shows that wheras bonobos chose the safe option and the risky option each about 50% of the time (where the dashed line is), the chimpanzees chose the risky option much more often. The graph on the right shows that both species chose the risky option more often in the "competition condition" than they did in the "neutral condition". Figure from Rosati and Hare's 2012 Animal Behavour paper.

These are interesting findings, especially when you consider the natural behaviors and lifestyles of these closely related species. Bonobos can be thought of as the hippies of the ape world, happily sharing and using sex to settle disputes and strengthen relationships. In comparison, chimpanzees are more like gangsters, aggressively fighting over resources and dominance ranks. So in general, the more competitive species is more likely to take risks. But when the social environment becomes more competitive, both species up the ante. This effect doesn’t seem to be simply the result of being in a social situation, because the apes didn’t increase their risk-taking in the presence of a playful experimenter.

This still leaves us with some questions to ponder though. Are apes more likely to take risks when an experimenter is offering food and taking it away because of a heightened sense of competition, or is this the result of frustration? And would we see the same effect if the “competitor” were another ape of the same species, rather than a human experimenter? How would their behavior change if they were hungry? These questions are harder to get at, but this research does demonstrate that like in humans, the decision-making process in chimpanzees and bonobos is dependent on social context.


Want to know more? Check this out:

Rosati, A., & Hare, B. (2012). Decision making across social contexts: competition increases preferences for risk in chimpanzees and bonobos Animal Behaviour, 84 (4), 869-879 DOI: 10.1016/j.anbehav.2012.07.010

The Best Dads in the Animal Kingdom

Paternal care is not nearly as common in the animal kingdom as maternal care, and for good biological reason. In most species, females produce fewer, larger, and costlier eggs than males do sperm. Therefore, it is usually beneficial to females to maximize the possible success of each one, sometimes by gestating them inside their own bodies (as mammals do), or incubating the eggs until they are ready to hatch (as birds do), or by providing prolonged protection, food and training until they are ready to take on the world for themselves. Males, on the other hand, are usually benefitted more by spending their time trying to mate with as many females as possible and avoiding the costs of parenting. But for some species, these costs and benefits of parenting are such that it pays for males to be good dads. Here are some of the best dads in the animal kingdom:

1. The Endurance Prize goes to the emperor penguin: Emperor penguins breed on the sea ice of Antarctica, the coldest place on Earth. After Mom lays her egg, her nutritional reserves are so depleted that she must return to the ocean (which can be over 100 miles away) to feed. This leaves the responsibility of keeping the egg warm through the freezing Antarctic winter to Dad. Dad goes months without feeding to balance the egg on his feet in subzero weather (-30 degrees Fahrenheit, on average) with freezing winds up to 120 mph, often forced to huddle together with other dads for warmth until their chicks hatch. If he moves too suddenly or the egg becomes exposed to the freezing temperatures, the chick will die. Even though he hasn’t eaten for months and has lost about 40% of his body weight, Dad provides the newly hatched chick with sustenance: a milky-type substance produced by a gland in his throat until Mom returns to the family with a belly-full of fish.

An Emperor penguin dad feeds his chick after a brutal winter without
eating a single bite himself. Photo by Mtpaley at Wikimedia Commons.

2. The Provider Prize goes to the water bug: Water bugs (also known as toe-biters) are huge, predatory, aquatic insects that can reach sizes up to 4 inches in length! They have a strong beak and a painful bite and they have been known to eat small fish, frogs and even birds! In order to grow into a large predatory insect, one must hatch from a large egg. Water bug eggs are so large that they require more oxygen for development than they can naturally absorb through the water. This requires a parent to help supply them with oxygen. However, Mom spends so much of her energy producing these humongous eggs that she doesn’t have enough energy reserves to then care for them. This leaves all of the parental duties up to Dad. In these species, Mom lays her eggs on Dad’s back in between matings. Once the full clutch of up to 150 eggs are glued to Dad’s back, he dances around and does underwater pushups to keep the water circulating and periodically takes them on a field trip to the surface for air (which has more oxygen that water does) until they hatch.

A water bug dad carries his eggs. Photo by Marshal Hedin at Wikimedia Commons.

3. The Protector Prize goes to the Darwin’s frog: Darwin’s frogs are small South American frogs that look a bit like a bloated leaf. When they mate, Mom lays her eggs in the leaf litter, which Dad fertilizes and then guards for a few weeks until the developing embryos begin to move. At that point, he “swallows” the eggs into a pouch near his throat called a vocal sac, where they hatch. He carries the tadpoles in his vocal sac until they have fully developed into frogs, at which point he “vomits” them up and they hop away to start their new lives. It’s pretty gross. Watch:

4. The Pregnancy Prize goes to the seahorse: Male seahorses have fewer (and thus more precious) sperm than males of other species and they are the only males that take on the full responsibility of pregnancy, carrying up to 2,000 babies at a time! Although they don’t have a mammalian womb and placenta, they do have an enclosed abdominal pouch specifically for the purpose of incubating the babies. Mom deposits her eggs in Dad’s brood pouch. He fertilizes them and incubates them in his expanding belly for 10-45 days (depending on the species). During this time, his body undergoes a number of hormonal and physiological changes and Mom never even makes an ice cream run for him or rubs his (non-existent) aching feet. When the babies are ready to emerge as fully developed little seahorses, seahorse dads even experience contractions as they give birth!

The best dad and grandpa in the world.
Photo by Sarah Jane Alger.

5. The Multi-Generational Prize goes to humans: Many human dads are not only good fathers, but also good grandfathers. Grandparenting is extremely rare in the animal kingdom (the first documented case of grandparenting in non-humans was as recent as 2008) and human males excel at it. They provide care, advice, lessons and resources to increase the success of their offspring and grand-offspring… It’s amazing other species haven’t picked up on this amazing secret yet!

Caught in My Web: The Intelligence and Creativity of Crows, Octopuses, Monkeys, Fish and Dogs

Image by Luc Viatour at Wikimedia.

For this edition of Caught in My Web, we marvel at animal intelligence.

1. Joshua Klein talks about crow intelligence and their potential for training in this fun TED talk.

2. Jason Goldman at io9 explains an amazing discovery that Atlantic cod can also innovate to solve problems.

3. Sarah Williams at Science explains research out of Harvard that shows that untrained rhesus monkeys can do math and we can use this to learn about how we think.

4. A veined octopus shows off his imagination as he creates a “hiding” place:

5. And last, but not least, three shelter dogs were taught to drive! Here are the results:

5 Animal Species With Surprising Memories

We often think of animals as having hilariously short memories – the “memory of a goldfish”, if you will. But many animals have memories that can put yours to shame.

There are many different kinds of memory and each of them is controlled differently by different parts of the brain. Short-term memory can be thought of as the brain’s scratch pad: It holds a small amount of information for a short period of time while your brain decides whether it is worth retaining in long-term memory or if it can just fade away. When a short-term memory becomes a long-term memory, this process is called consolidation and involves physiological changes in the brain.

Long-term memory can be further divided into two main types: procedural memory and declarative memory. Procedural memory is used to remember how to do things and what objects are needed to do those things. Declarative memory is used for recall and can be further divided into memory used to recall facts (semantic memory) and events (episodic memory).Each of these different types of memories are stored in different parts of the brain. Furthermore, different types of facts (remembering faces versus numbers, for example) and different types of events (depending on if they have an emotional component or not, for example) are also stored in the brain differently. Because species differ in how we rely on our brains, it makes sense that this might be reflected in our abilities to remember in different ways.

So let’s check out some of the most amazing memories in the animal kingdom:

Do you know what all your kids and nieces and nephews are
doing right now? These elephants do. Photo by PJ KAPDostie
at Wikimedia.

1) They say an elephant never forgets. Elephants are very social animals that live in large stable herds. This has led to some incredible feats of social memory. They can keep track of the whereabouts of 30 group members at once and they can remember an animal they briefly met over 20 years ago. For an animal that lives about 50 or 60 years, this is very impressive. Elephants also have outstanding episodic memory: In 1993, Tarangire National Park in Tanzania suffered the worst drought that it had seen in 35 years. It was so severe that it killed 20% of elephant calves, compared to the average loss of about 2%. Of three herds that lived in the park in 1993, two of them were led by females that had lived during the severe droughts of 1958-61 and those herds left the park and were more successful at finding food and water. The herd that stayed was led by a younger female that had never experienced such a severe drought and that herd suffered 63% of the total mortality.

Dolphins never forget a name. Photo from the
NOAA Photo Library available at Wikimedia.

2) Bottlenose dolphins have even more incredible social memories. They, like elephants, live in complex social groups. Each dolphin has a unique whistle that it uses like a name. When they are played recordings of whistles of companions they lived with years or even decades earlier, they approach the speakers for longer than when they are played the whistles of dolphins they never met. The fact that they, like elephants, remember companions for over 20 years is much more impressive because their lifespan is only 40-50 years!

Sea lions can remember
meaningless tricks for years.
Photo by LSA2886 at Wikimedia.

3) Sea lions have amazing procedural memory. In 1991, marine biologists at the University of California, Santa Cruz, taught a California sea lion named Rio a card trick. They held up one card with a letter or number on it and another set of two cards: one that matched the first card and one that did not. Rio learned to pick the matching card to be rewarded with a fish. Everyone was impressed and she didn't do the trick again... until 10 years later, when researchers pulled out the cards and asked her to do it again. Rio had the same score in 2001 with no practice that she did in 1991 when she originally learned the trick!

Clark's nutcrackers can remember where they stashed
30,000 pine nuts.I can't even keep track of my keys.
Photo by Gunnsteinn Jonsson at Wikimedia.

4) Clark’s nutcrackers can remember the exact location of 30,000 pine nuts. This kind of superhero ability is born out of necessity: nutcrackers completely rely on their caches of food to get them through the winter. However, despite their amazing long-term spatial memory, their short-term memory is below average: they can’t even remember the color of a light for 30 seconds.

5) Chimpanzees can put your working memory to shame. Working memory is a form of short-term memory that is applied to a task. A group of researchers taught chimpanzees to do a task in which they were shown the numbers from 1-9 in random locations on a computer screen. When the numbers are covered, chimps can remember where each number was. Furthermore, they only need to see these randomly placed number for a few seconds to get this task correct. In comparison, only people that are considered savants have comparable abilities.

Effects of Iron Deficiency in Female Runners (A Guest Post)

By Ana Breit

When people think of nutritional deficiencies, they probably picture women with goiters due to lack of iodine or other newsworthy examples. In reality, the most common nutritional deficiency in the United States is iron deficiency. Iron Deficiency (ID) is especially common in endurance athletes, especially female athletes.


Start of 2013 Roy Griak Invitational Cross Country Meet at
the University of Minnesota. Photo courtesy of Jennifer Larson.

Iron is the metal in humans that allows oxygen to be carried in our bloodstream to all of our other organs. Without enough iron, less oxygen is taken to the muscles and other organs that need it. People with anemia (iron deficiency) may experience fatigue, weakness, and dizziness. Scientists Irena Auersperger, from the University of Ljubljana in Slovenia, Branko Skof and Bojan Leskosek, both from the University Medical Centre in Ljubljana, Slovenia, Ales Jerin, from the University Clinic Golnik in Golnik, Slovenia, and finally Mitja Lainscak, from Campus Virchow-Klinikum in Berlin, Germany asked how iron levels affect performance levels in female runners and whether or not intensified training impacts various iron parameters.

Fourteen moderately active women were chosen to participate in the study. In order to be enrolled they had to have regular menstrual cycles, eat animal products on a regular basis, and not be taking forms of medication except birth control. Each woman was put into one of two groups based on her ferritin levels. (Ferritin is a protein that stores iron). Anyone with ferritin levels greater than 20 micrograms per liter was put in the Normal group (for normal iron stores). Anyone with ferritin less than or at 20 micrograms per liter was put into the Depleted group (for depleted iron stores).

The study took place during a training period leading up to the International Ljubljana Marathon. During the eight week training period, runners had routine tests consisting of a 2400 meter (1.5 miles) time trial on a standard 400 meter outdoor track. Blood samples were taken at three different times: once before the eight week training period, once after the training period, and once more ten days after the marathon. These measurement times will be referred to as baseline, training, and recovery, respectively. Height, weight, and body fat percentage were measured during baseline and at recovery. Each woman then ran on a treadmill so researchers could measure her maximum speed, maximum oxygen consumption (VO2 max), and heart rate. Blood samples were taken at baseline, training, and recovery points to measure various blood parameters and iron parameters.

Both Normal and Depleted groups had similar body measurements, VO2 max, and heart rates. Both groups had improvements in their endurance measurements, however, only the Normal group had endurance improvements that could be documented as significant while the Iron Deficient group’s endurance improvements were less. By the end of the experiment, most of the runners were anemic. Both groups experienced a decrease in iron levels during the training and recovery periods compared with the baseline levels. Overall, both groups’ iron levels decreased in all areas during the training phase, even though they were both getting stronger and faster. The group that started out with lower iron levels did not show as great of an improvement as the group with the normal iron levels at baseline. Even after the 10 day recovery period, iron level parameters were still considered low. With this data, the researchers agree that Iron Deficiency decreases performance levels of female athletes.

Even though most people consider running to be a very healthy pastime, it can have undesired negative effects as well. All endurance athletes, especially female athletes, should have their iron levels checked regularly, and should make a conscious effort to incorporate iron into their hopefully already healthy diet by eating any enriched grains and a healthy amount of red meat. With consent of a physician, iron supplements can also be a good way to keep iron levels in check.

Bibliography

Auersperger I, Škof B, Leskošek B, Knap B, Jerin A, & Lainscak M (2013). Exercise-induced changes in iron status and hepcidin response in female runners. PloS one, 8 (3) PMID: 23472137

War and Peace



A group of Gelada baboons in Ethiopia.
Photo by A. Davey at Wikimedia Commons.

Syria and Iraq. Ukraine. The Gaza Strip. People are dying in large numbers at the hands of other humans, and for what? Land and resources? Is it really worth it? It is often said that humans are the only species so horrific as to kill its own species in war. But the fact is, we are not alone in what was previously thought to be a uniquely human trait. In many animal groups, individuals will band together in collective defense of territory and resources.

This week at Accumulating Glitches I talk about how group size influences the ability of primate groups to hold their territories. Check it out here.

And to learn more, check this out:

Willems, E.P. Hellriegel, B. and van Schaik, C.P. The collective action problem in primate territory economics, Proceedings of the Royal Society B, 280: 20130081 (2013). DOI: 10.1098/rspb.2013.0081.

Caught in My Web: Chimpanzee Memory, Beatbox-Dancing Cockroach Legs, Cute Animals Behaving Badly, Behavioral Catastrophe, and Scientifically Accurate Spider Man

This week in Caught in My Web, I share some quirky web pages that open our eyes to some aspects of animal behavior that we don't often think about:

1. Lee Rannals describes on redOrbit research that discovered that chimpanzees use long-term memory of how various trees produced fruit in previous years to forage today.

2. On TEDEd, Greg Gage hooks up a cockroach leg to a device that allows us to hear nerve impulses! And if that wasn’t cool enough, he then gets the cockroach leg to dance to a human beatbox. You have to see this.

3. Cute animals behaving badly. Need I say more?

4. Animals will sometimes continue their behaviors even when they end in catastrophe. George Dvorsky at IO9 describes 8 of the most deadly.

5. And if ADHD's Scientifically Accurate DuckTales was too much for you, DO NOT WATCH Scientifically Accurate Spider Man:

Caught in My Web: What Your Dog Really Thinks About You, Understanding Gestures, Camera Traps and Pruney Fingers

Image by Luc Viatour at Wikimedia Commons.

This week in Caught in My Web, I share what I found when pondering interactions between humans and animals, what we have learned from camera traps, and what our pruney fingers in the bath may have to teach us about our animal nature.

1. Greg Berns, a psychiatry professor at Emory University, set out to use an fMRI scanner to learn more about what dogs think about their humans. Read his story here at Psychology Today. And check out this video describing The Dog Project:

2. Although dogs may be “man’s best friend”, they have failed numerous tests in understanding our gestures, such as pointing, without training. Even chimpanzees require training before understanding the meaning of human pointing. But elephants are now the first non-human species that seems to innately understand human pointing, naturally investigating objects pointed to (comparable to a 1-year-old human). Jack Flanagan discusses this research at NewScientist.

3. At The Thoughtful Animal, Jason Goldman discusses camera traps (weather-resistant cameras that use motion detection sensors to photograph wildlife) and how they are used in animal research. He also reveals the secret ingredient to luring jaguars to the cameras at You’ll Never Guess How Biologists Lure Jaguars To Camera Traps.

4. While we’re talking about camera traps, Siberian tiger researchers set up camera traps in southeastern Russia. One of their cameras took a series of 3 amazing pictures of a golden eagle attacking a sika deer. Check out the pictures at National Geographic.

5. Ever wonder why your fingers get pruney in the bath? Maybe it is a primate adaptation! Mark Changizi explains why at TEDEd: