IS PLAY the new tool use? A recent recounts bumblebees rolling tiny wooden balls, not for a reward, but apparently just for fun. The authors conclude that the behaviour fulfils the criteria for play, with one : “It goes to show… that despite their little size and tiny brains, they are more than small robotic beings.” Put another way, bees just wanna have fun, and that presumably makes them more like people.
This discovery underscores a long-standing conflict in our view of animals. On the one hand, we want to find the features that distinguish humans from other animals: tools, language, a theory of mind (in which animals can infer the mental states of others). On the other, we delight in finding animals that breach those boundaries: chimps, crows and now bees that use tools, dolphins with signature whistles. But what do those boundaries mean?
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Not much, or at least not what people sometimes think. As an evolutionary biologist who studies animal behaviour, I am bemused by this effort to rank animals by their capabilities. The ranking is wrong not because animals lack amazing abilities, but because evolution doesn’t produce an organisation like the military, with the equivalent of amoeba privates and primate generals. Instead, everything that is alive today is just as evolved as everything else. Some species (crocodiles and cockroaches, for instance) look more like their ancient ancestors than others and may well behave more like them, but that doesn’t mean some creatures are more or less highly evolved than the rest.
You might think that calling attention to bees and other animals that do things we didn’t think they could do would be a way to circumvent this ranking and make our view of nature more realistic. But it isn’t. It is pointless to elevate creatures, whether bumblebees or chimps, so that we can put them in an exclusive club that used to only contain humans.
Underpinning these efforts is a desire to show that animals, even tiny ones with lots of legs, are like us and shouldn’t be dismissed as automatons. I applaud that desire. But we can recognise animals for what they are, and be awestruck at their abilities, without having to make their behaviour mirror that of humans. Bees may play, but that doesn’t mean they are like children with exoskeletons.
Once we get out from under the tyranny of those rankings, of thinking that animals have to be like people with human motivations and feelings, we are freed up to consider the mechanisms behind the behaviours. Often, that involves convergent evolution. For example, the same neurotransmitter – serotonin – influences anxiety in humans and maze exploration in crayfish. In a tank divided into well-lit and shadowy areas, , but prefer the dimmer areas, consistent with their nocturnal lifestyle. Crayfish stressed by mild electrical shocks avoided the light sections of the maze, a response that was linked to their serotonin levels and that could be altered by a serotonin inhibitor.
Does this mean crayfish experience anxiety? No, it just means that evolution co-opts similar pathways to produce different results. In the bees’ case, they might be exhibiting some very interesting behaviour that has nothing to do with wanting to “have fun” – but we will never examine it if we simply assume they are playing just like people. I am not disparaging the bee researchers’ conclusions, and I am not trying to be a killjoy, but there is something about all this anthropomorphising that stifles enquiry, instead of encouraging it.
If we can let go of the impulse to rank animals, we might find out that our intuition is wrong. And being wrong is one of the most productive things about science.
Marlene Zuk is an evolutionary biologist and author of .
