Mother mongooses may risk death to protect unborn children

Mongooses risk their own survival to protect their unborn children through a remarkable ability to adapt their own bodies, says new research published in Frontiers in Ecology and Evolution.

Pregnancy can takes a physical toll that, according to some theories, may increase the mother's levels of toxic metabolites that cause oxidative damage.

Increased oxidative damage can cause complications during pregnancy, but these results show how some mammals have evolved to specifically minimize such damage, albeit only temporarily.

"We think mother mongooses shield their offspring by reducing their own levels of oxidative damage during breeding;" explained Dr. Emma Vitikainen of the Centre of Ecology and Conservation at the University of Exeter, and lead author of the study, "However, she could be trading her own long term well being for the short term benefit of protecting the growing pups."

Vitikainen and her colleagues followed groups of wild banded mongooses over five years, measuring oxidative damage markers, as well as the animals' health and survival. Oxidative damage is a normal byproduct of metabolism throughout an animal's lifespan, but they found that pregnant mongooses showed lower than expected toxin levels, refuting current theories that damage increases during pregnancy.

The mongooses with the least evidence of oxidative damage were also the most successful at reproducing. They had the largest litters of pups, and these pups had higher chances of surviving to independence. Not all mongooses showed the same protective capabilities however, and mongooses with more oxidative damage produced pups with lower survival rates, while also being in poor health themselves.

This shielding effect may be partially explained by changes in the content of the mother's' blood, but the details are not yet fully understood. "Our study shows that mothers might be adjusting their physiology," said Vitikainen; "It would be quite a remarkable adaptation."

Vitikainen also found that this effect was only temporary and that oxidative damage returned to normal levels after pregnancy. This suggests that the protective mechanisms during pregnancy may be unsustainable and that they have long term, potentially harmful, consequences for the mother's survival.

"An important subject for future research is to determine whether the changes that happen in pregnant mothers are there to benefit the mother, child, or both;" continued Vitikainen; "If there are negative consequences for mothers, we'd like to understand how they could be mitigated."