The wild can be ‘death trap’ for rescued animals

(Press-News.org) An important new study has found that the wild can be a “death trap” for animals that are released from captivity after previously being rescued.

The research, published in the journal Global Ecology and Conservation, involved Anglia Ruskin University primatologist Professor Anna Nekaris OBE and colleagues from the NGO Plumploris e.V. and the University of Western Australia, who studied the outcome of Bengal slow lorises (Nycticebus bengalensis) released in Bangladesh.

Slow lorises, with their large eyes and “cute” appearance, are one of the world’s most trafficked primates and are highly sought after in the illegal pet trade.

The International Union for Conservation of Nature classifies all slow loris species as either Critically Endangered, Endangered or Vulnerable, which also makes them a popular species for rescue and release projects.

However, this new study indicates that well‑intentioned releases can be fatal for these small, nocturnal primates. Using radio collars, the researchers tracked the progress of nine animals released in a national park in northeastern Bangladesh, which is a site that has been used for previous releases.

Out of the nine Bengal slow lorises released into the forest, only two survived. Three animals died within just 10 days, and another four within six months. Of the seven that died, the bodies of four were recovered and all had been fatally attacked by other slow lorises.

Slow lorises are highly territorial and are the world’s only venomous primate, possessing sharp teeth used to inject their venom. The recovered animals showed clear bite wounds to the head, face and digits, indicating that territorial conflicts led to their deaths.

The study also found that lorises that spent longer in captivity prior to release survived for fewer days in the wild and that the released lorises showed elevated levels of movement and alertness compared to that typically displayed by wild Bengal slow lorises.

The two individuals that survived had a greater range compared to those that died, suggesting their success depended on moving away from established territories of other slow lorises and avoiding attack.

Unlike larger, more “charismatic” species such as big cats, which are typically closely monitored after release, the study highlights how the fate of the majority of species released back into the wild often goes unreported.

The researchers highlight the importance of thoroughly understanding the suitability of both the release site and the animal being released, with site assessments, long‑term monitoring and species‑specific rehabilitation guidelines necessary for effective releases.

Senior author Anna Nekaris OBE, Professor of Ecology, Conservation and Environment at Anglia Ruskin University in Cambridge, England, and head of the Little Fireface Project, said: “It’s assumed that returning confiscated or rescued animals to the wild is always a positive conservation story. Our research shows that for highly territorial species like slow lorises, releasing them into areas that are already densely populated can be a death trap.

“Many rescued endangered species are often released because the public expects it, but for animals such as the Bengal slow loris, this is not always the best course of action. Without fully understanding the animal’s behaviour, its time spent in captivity and the density of resident populations at the release site, reintroductions may do more harm than good.”

Lead author Hassan Al-Razi, the team leader of Plumploris e.V. Bangladesh, said: “Rescue and release have become an increasingly common practice in Bangladesh. Many wild animals, including slow lorises, are rescued and subsequently released back into the wild.

“However, in many cases, these releases are conducted inappropriately. For forest-dwelling species, release sites are often selected based on logistical convenience rather than ecological suitability. As a result, certain forests have effectively become dumping grounds for rescued animals and are no longer appropriate release sites.

“Although our research has focused on the Bengal slow loris and demonstrated the consequences of such practices, we believe similar patterns likely affect many other species.”

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