At first glance, this doesn’t seem like the best approach to parenthood – but researchers in the UK say it’s a good thing and may even shed light on how the concept of fairness has evolved.
The fact that virtually all mammals give birth at the same time creates what researchers call a “veil of ignorance,” and that means parents give equal care to all mongoose puppies – giving a group a common litter of 20 puppies. – a better chance of survival.
“In most of the natural world, parents favor their own young,” Harry Marshall, senior lecturer in zoology at the University of Roehampton, said in a press release.
“However, in banded mongooses, the evolution of remarkable synchrony of births has led to the unusual situation that mothers do not know which young are theirs and therefore cannot choose to give them additional care.”
Researchers studied the behavior of seven groups of banded mongooses, small feline creatures with dark bands on their backs found in parts of Africa, Uganda. Half of the pregnant mothers in each group received 50 grams of cooked eggs each day, while the other half received no additional food.
Mongooses that received the extra food gave birth to larger offspring than those that did not, but these body weight differences did not persist as mongoose moms provided extra care to the smaller ones.
“This ignorance of kinship with puppies is key. Our study tests and finds support for the theory that where such ignorance exists, individuals should choose to invest in the poorest offspring and the” upgrade. “They’re doing it because, to their knowledge, this inferior offspring might be theirs,” Marshall explained in an email to CNN.
“Our study shows that fairness can evolve in animal societies, and is not just a concept for humans.”
The researchers said mongoose moms nurse all the puppies in their underground dens for a month, without any discrimination, and the puppies feed on many different moms. Once the puppies come out of the den, they form one-on-one relationships with adults, called escorts, who can be any adult male or female.
They nurture and protect the puppy in their care until they can find food for themselves around 90 days of age.
“Escorts individually recognize and preferably respond to calls from ‘their’ particular puppy and actively search for their puppy if they are separated or lost,” said the study, published Wednesday in the journal Nature Communications.
“Puppies, on the other hand, aggressively defend access to their escort and continually beg for food.”
The study indicated that it was synchronous birth that was the key to the success of extreme teamwork because on the rare occasions that mongoose moms do not deliver at the same time, females kill other females’ puppies instead. than to take care of it.
It is not clear exactly how mongooses orchestrate reproduction at the same time – sometimes it can involve as many as 12 female mongooses. One hypothesis, Marshall said, is that dominant females produce a pheromone that acts as a signal. However, as the birth takes place in an underground den, it was not possible to observe the synchronized arrivals.
“When they don’t, the litter almost always dies very soon after,” Marshall said.