Many different species have many different temperaments’. Many of us have bared witness to mbuna bossing tilapia, terrible Tangs, or cut throat crab pincers heading your way, their owners not caring you tower over them. Our flighty friend’s behaviours results from natural selection often favouring high levels of (seemingly!) undirected anger. But the more astute amongst us have noticed that even within species not all anger is equal.
I don’t think it’s a stretch to say that we are all aware that our furrier friends possess distinct personalities (and don’t mean the hirsute amongst us!). Cats and dogs vary in how they react to the world around them. Even within litters, brothers and sisters, like us, can be quite different from one another.
Up until fairly recently the animal behaviour boffins might have agreed with that limited assessment but nowadays we are seeing more and more evidence that all manner of life, including our aquatic pals, possess minds of their own. Not to make things easy, scientists love to make up jargon, we call personalities “behavioural syndromes”. We describe personality, in its simplest form, as exhibiting similar responses to stimuli across contexts. That last bit is the key, the across contexts bit. We all know someone who is perpetually peeved, nearly always outraged or more often than not, naughty. You describe people by their personality as it’s something that consistently explains them.
In science many of us would love to work lions, eagles and crocodiles, all at once ideally. But we face up to the fact that the most charismatic of fauna are rarely controllable, allowing us to study them in a controlled way. As a result we use ‘models’ (sadly, no, not that type of model) which are easy to keep, do well in captivity yet reveal natures inner secrets. You may be surprised to know that many of our easy to keep pals have been used by scientists for a long time now. Danios are by the most common fish used in science, guppies are not that far behind and sticklebacks get more than their fair share of grant money. It’s these species that scientists have turned to when the eagles teamed up with the lions who rode the crocodiles through the laboratory, eating all before them.
A lot of what we know about the scientific nature of personality comes from work with guppies. They are often split into bold or shy categories; bold individuals are often also aggressive. Nature likes variation and sometimes the bold bad boys win the girls whilst at others the shy types do the charming as the explorers have all been gobbled up. Sticklebacks have shown us that when shoaling some individuals always lead the way while Danios have shown us that individuals can be always reactive or proactive to situations. I hope that we are all starting to see our fishy friends as more than autonomous robots as personality goes a long way.