Kristin Hugo
The African big cats give birth around the same time so that they can take care of each other's cubs.
While researching lions in Zambia, biologist Thandiwe Mweetwa noticed that lionesses within a pride will all have cubs around the same time.
When she looked into it further, Mweetwa learned lionesses sync their fertility cycles so that they can all raise their young together.
There's a reason for that. “Synchronized estrus is thought to increase reproductive success in the pride,” says Mweetwa, a National Geographic emerging explorer and Big Cats Initiative grantee. Having cubs at the same time means that mother lions can rely on each other to nurse, babysit, and protect the youngsters.
This safety in numbers also allows more lions to survive to adulthood. Predation is a great threat to small, vulnerable babies in any species, but if all babies are born at the same time, there are only so many that predators can eat.
If young are born at different times throughout the year, predators could use them as a steady source of food.
Even so, many still die: More than half of all African lion cubs don’t make it past their first year. They're at risk from predation, disease, abandonment, starvation, and being killed by an outside male.