Baby chicks can flee away from predators from the first moments of life, they do not learn from experience. That is what emerged from a study conducted by the University of Trento with Queen Mary University of London.
The research team also found out that baby chicks can slow down or stop moving to avoid being noticed when a predator is still distant.
The study, which appeared yesterday in PNAS, demonstrates that this ability is innate and is not learned through experience.
Using appropriate antipredatory responses is crucial for survival and, when preys meet predators, there is no time for trial and error learning because it takes time and a mistake can cost you life. This made the researchers suppose that the ability to flee or to freeze does not require learning, but they could not be sure of that with the data they had.
The research teams carried out some experiments with newly hatched chicks with no experience with moving objects.
When exposed to an approaching predator (a looming stimulus over their heads, like a bird of prey), or when presented with a distal threat (a large object moving quickly over their heads, like a predator searching for a prey), the baby chicks displayed an appropriate response. They try to escape quickly from approaching threats, and decrease their speed to avoid detection when the threat is moving in the distance.
Experiments of this kind can be carried out with baby chicks because they are able to move and to feed soon after hatching. At that age, chicks also have a relatively mature sensory and motor system.
Little is known about their early behaviour and about the neuronal mechanisms that determine the responses to visually detected threats. These reactions to rapidly approaching stimuli can be observed in newborn babies too, while the freezing response can be observed also in adult humans in life threatening situations, like in a fire or in case of sexual abuse.
This type of experiments can open the way to studies focused on molecular mechanisms and on individual responses, which have both genetic and environmental bases.
The press release (PDF | 106 KB) includes the comments of Elisabetta Versace, former post doc researcher at the University of Trento and currently Lecturer at Queen Mary University of London; Giorgio Vallortigara, head of the research team at the University of Trento; and Marie Hébert, researcher at the University of Trento and first author of the study.
About the article
The article, Inexperienced preys know when to flee or to freeze in front of a threat, was written by: Marie Hébert, Elisabetta Versace, Giorgio Vallortigara, and was published in PNAS on 28 October 2019.
DOI: www.pnas.org/cgi/doi/10.1073/pnas.1915504116