Scientists set up a trap cage to catch wild boars and set up cameras to record movement. They ended up capturing a wild boar lifting a wooden log to open the cage and free two other wild boars caught in it - the first observed case of rescue behavior among wild boars.
Rescue behavior in animals is a form of prosocial action in which one individual (rescuer) frees another individual (victim) in an unpleasant or dangerous situation.
Rats freeing restrained cagemates and ants rescuing members of their colony trapped in a nylon trap buried in the sand are concrete examples of this phenomenon.
Rescue behavior differs from other forms of assistance in its complex organization. To qualify as rescue behavior, it must meet four requirements.
First, the victim must be in distress in a situation that poses a physical threat, such as injury or death.
Second, the rescuer puts himself at risk in trying to free the victim; attempting to rescue represents a potentially large cost to the rescuer and is therefore viewed as an extreme form of pro-social behavior.
Third, the actions of the rescuer are adequate to the victim's situation, even if the rescue attempt is unsuccessful.
Finally, there is no immediate benefit to the rescuer in the form of food rewards, social contact, protection, or mating opportunities.
Scientists have published their research in the journal Nature, we report the first observation and photographic documentation of a potential case of rescue behavior in wild boar (Sus scrofa), a species that, due to its nocturnal activity, is rarely studied in the wild for social cognition. In the observed case, an adult female freed two young boars from the trap cage.
The incident was captured by a trap camera set to shoot every two minutes and set to monitor the visit to the corn bait trap.
The traps are used for individual marking of wild boars, which are part of the study of the ecology of movement and prevention of African swine fever.
The incident occurred on the night of January 28-29, 2020 and is captured in 93 photographs. Two boars were caught together for 2 h 35 min. The rest of the boars arrived at the capture site after 2 hours and 6 minutes and made an obvious rescue effort.
The entire event lasted 29 minutes and included several targeted attempts to remove the logs from the trap doors. They were successfully removed after just 6 minutes.
From the sequence of photographs, it can be seen that the female began her rescue immediately after arriving with her group at the capture site, and the group left immediately after the caught wild boars were released.