On cats AND squirrels

This week, I have things to say about two of my favorite species, cats and squirrels...

How can we know that cats love us?

A recent article in the Atlantic discussed the "love hormone" oxytocin, and how it is released when we interact with our pets (turns out other animals have it too, and their oxy levels may go up after interactions with US too).

Most studies have been on dogs, and one study showed that the effects of interacting with cats were less "loving" than interacting with dogs. Most research on human-pet attachment also finds reports of stronger attachment to dogs than cats. Why is this? Are our relationships with cats that different than those with dogs? Are the scales flawed? Is it our co-evolution with dogs that leads to this oxy release? There are still many unanswered questions.

Of course, other studies have suggested that cats aren't attached to humans (my feelings about that study can be found here)...and everyone just wants to know: DOES MY CAT REALLY LOVE ME????? So what gives? I talked about it with the Dodo this week (and so did John Bradshaw!).

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The evolution of self-control

How does cognition evolve? A group of scientists from around the world (led by Duke's Brian Hare, Evan MacLean and Charlie Nunn) got together to discuss how different cognitive tests could be compared across species and the findings were recently published in PNAS. Two of these tasks are classic tasks that measure "inhibition" or executive control - the A not B task and the cylinder task.

baitng the cup
baiting the cup

The A not B task is also known as a "perseverative error" - this task was developed by Piaget  - where a toy is hidden in one location for several trials, then moved to the opposite location on the test trial. The question is: will the participant search in the old location or the new? Surprisingly, young children continue to search in the original, not new location.

The cylinder task involves training an animal to approach a food reward via the side opening of an opaque cylinder; once they demonstrate the ability to do so, they are tested with 10 trials on an identical, transparent container. The test is whether they can "inhibit" the response to directly approach the food and still enter through the side of the container.

These two identical tasks were tested in multiple species, including coyotes, wolves dogs, many primates, birds and even elephants. I was lucky to be a co-author and part of this project and my advisor and I collected the data on fox squirrels and Mongolian gerbils. Turns out we were the only lab to contribute data on wild animals (the squirrels)!

The general findings were that absolute brain size was the best predictor of self-control. This might be in part due to the increased computational power a bigger brain affords one. In primates, a more complex diet also contributed to success on the two tasks.

A squirrel chooses the center cup instead of one of the end cups.
A squirrel chooses the center cup instead of one of the end cups.

So how did the rodents do? Well...some squirrels and gerbils (about half) did very well (above 70% correct), the rest did not do so well...suggesting a range of inhibitory control in both rodent species. There may be some individual differences at play here, and it would certainly be interesting to explore how those differences could be correlated with other cognitive abilities or personality traits!

You can also read the Phys.org or National Geographic summary of the study, or access the full paper here.

Watch a video of the squirrel failing at the cylinder task:




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