Scientists documented how boars rescued congeners by opening trap doors

Scientists set up a cage trap to catch wild boars and installed cameras to record movement. They ended up capturing a boar lifting a wooden log to open the cage and free two other boars trapped in it, the first observed case of rescue behavior among wild boars.

Rescue behavior in animals is a form of prosocial action when one individual (rescuer) releases another individual (victim) in an unpleasant or dangerous situation.

Rats releasing restrained cage mates and ants rescuing members of their colony caught 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 or herself at risk by attempting to free the victim; the rescue attempt represents a potentially high cost to the rescuer and is therefore seen as an extreme form of prosocial behavior.

Third, the rescuer’s actions are appropriate to the victim’s situation, even if the rescue attempt proves unsuccessful.

Finally, there is no immediate benefit to the rescuer in the form of food reward, social contact, protection, or mating opportunities.

Scientists published their study in the journal Nature, we report the first observation and photodocumentation of a potential case of rescue behavior in wild boar (Sus scrofa), a species rarely studied in the wild from a social cognition perspective because of its nocturnal activity. In the observed case, an adult female freed two young boars from a cage trap.

The incident was captured by a trap camera set to shoot every two minutes and set to monitor the cornbait trap visit.

The traps are used to individually tag wild boars as part of a study of movement ecology and African swine fever prevention measures.

The incident occurred on the night of January 28-29, 2020 and is captured in 93 photographs. Two boars were caught together at 2 h 35 min. The remaining boars arrived at the scene of capture 2 hours and 6 minutes later and conducted an apparent rescue.

The entire event lasted 29 minutes and included several deliberate attempts to remove the logs covering the trap doors. They were successfully removed after only 6 min.

The sequence of photos shows that the female began her rescue immediately after arriving with her group at the trapping site, and the group left immediately after the captured boars were released.

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