When it comes to learning how to avoid predators, damselfish start early. Even as an embryo, they develop an understanding of how to survive.
The world’s oceans are full of things waiting for a chance at a meal. Fish in their larval stages are particularly vulnerable to being snatched up by a predator, and of the masses of eggs produced, only a small proportion make it to adulthood. The ability to recognise the tell-tale signs of a predator as early as possible can give a young fish making its first forays an extra chance at survival.
By monitoring heart-rates, a team of researchers discovered that embryonic cinnamon clownfish (Amphiprion melanopus) react to alarm cues from other damselfish nearby. With the addition of a predator odour during testing, the embryos were even found to learn and associate that predator with the alarm cues.
Being able to recognise a predator by smell early on, and be aware of its potential threat, gives a newly-hatched damselfish a small but potentially life-saving advantage. With this information, the youngster is able to adjust its behaviour to enhance its own survival chances during those dangerous early days in its new ocean world.
Atherton, J & McCormick, M. (2015). Active in the sac: damselfish embryos use innate recognition of odours to learn predation risk before hatching. Animal Behaviour, doi:10.1016/j.anbehav.2015.01.033
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