Adoption, a common practice among humans, has also been observed in the animal kingdom, raising intriguing questions about the motives and benefits behind such behaviour.
While humans adopt for various reasons, animals, too, seem to engage in adoption for purposes that extend beyond mere altruism. Recent studies shed light on the fascinating world of animal adoptions and hint at their potential evolutionary advantages.
Animals adopting unrelated offspring may seem counterintuitive, but according to Michael Weiss, a behavioural ecologist and research director at the Center for Whale Research in Washington State, this behaviour can confer evolutionary advantages to the adoptive parent.
Weiss suggests that caring for parentless infants may provide valuable caregiving experience, particularly for females without offspring, enhancing their chances of future reproductive success and the survival of their own young.
Inter-species and Intra-species adoption
While intra-species adoptions, where animals adopt infants of the same species, are relatively well-documented, some cases of inter-species adoptions have baffled researchers.
A 2021 study published in the journal eLife detailed how young mountain gorillas forged relationships with dominant males in the absence of their mothers.
The presence of these orphans offered an opportunity for dominant males to showcase their caregiving skills, potentially increasing their chances of mating and passing on their genes.
Cross-species adoption adds a layer of complexity to the phenomenon. Researchers documented cases of great apes adopting infants from separate groups. Female bonobos, in particular, appear to adopt infants for reasons ranging from forming future alliances to an innate fascination with babies.
These adoptions bridge social groups and showcase the intricate social dynamics that can influence such behaviour.
The Orca mystery
Not limited to primates, adoption has also been observed in orcas, sparking curiosity and debate among researchers.
In 2021, a remarkable incident was observed in Iceland, where an orca appeared to adopt a baby pilot whale. Subsequent instances of orca adoption raised questions about the motivation behind such behaviour and its potential effects on the adoptive parent's reproductive success and existing offspring.
Complexity of animal adoption
While animal adoption can offer evolutionary advantages, it has challenges. Competing demands for attention between adoptive and biological offspring may lead to negative outcomes, such as decreased survival rates or altered behaviours.
In some instances, inexperienced mothers may adopt offspring from other species or struggle with the demands of parenting, providing insight into the nuanced nature of this behaviour.
While evolutionary pressures shape animal adoptions, researchers emphasize that individual cases may have unique motivations.
For instance, orcas, with their complex brains and instincts, may adopt for reasons beyond immediate survival or reproductive advantage. The mystery surrounding these behaviours highlights the depth of our understanding and the complexity of the animal kingdom.