Primates are known both to grieve their loved ones and practice cannibalism, but for the first time, scientists have recorded a Tonkean macaque eating her dead baby.

Researchers studying macaques at the Parco Faunistico di Piano dell’Abatino animal sanctuary observed a new mother named Evalyne "caring" for her deceased infant for weeks, and then consuming its mummified body until nothing but a single bone remained.

Tonkean macaques—which are native to Southeast Asia—tote around their babies' corpses for hours or, even days. It could be a manifestation of grief, or an absence of understanding that the offspring is dead.

“This kind of behavior has been documented in chimpanzees and a few other primates, with mothers carrying their dead infant until it disintegrates,” notes Frans de Waal, a primatologist at Emory University who was not involved in the new research.

View Images Evalyne nibbles on the mummified body of her infant. Photograph by Arianna De Marco

But "the new part here is the cannibalism,” says de Waal. “Macaques do not normally eat each other.” (See "Cannibalism Study Finds People Are Not That Nutritious.")

Not only do Tonkean macaques not eat their own kind, “they are a vegetarian species and never eat meat," adds Arianna De Marco, an evolutionary biologist at Fondazione Ethoikos in Italy who led the research.

'Curious and Moved'

Infant death is common among first-time macaque mothers in the wild and in captivity. Of the 51 total births at the sanctuary, 16 baby macaques died or were stillborn.

After her infant died at four days old, Evalyne became agitated, staring and screaming at her own reflection in her enclosure’s door, a behavior not seen before, says De Marco, whose observations are published this month in the journal Primates.

She then continued to groom, lick, and carry the dead infant, even when the body had fully mummified on the eighth day and its head fell off on the 14th. Mummification preserved the shape of the body, which could be one of the reasons why she continued nurturing the dead body, De Marco adds.

View Images The first-time mother seems to try to comfort the skeleton of her baby, which died four days after birth. Photograph by Arianna De Marco

“I was both curious and moved at the same time,” De Marco says. (Also see "Pictures: Gorilla Mother 'Mourns' Dead Baby.")

When the rest of the infant fell apart and its hair came off in the third week, Evalyne was seen nibbling on her infant’s remains. At least one other macaque species has been recorded eating infants: Taihangshan macaques of China. Bonobos and chimpanzees also sometimes practice infant cannibalism.

View Images Many primates carry their dead infants for days, but rarely do they eat them. Photograph by Arianna De Marco

Tough Love

“It is difficult to give an explanation for this behavior,” says De Marco, adding it may occur in the wild, too. “The dramatic change of maternal behavior from caretaking to cannibalistic attitude is astonishing."

View Images Evalyne ate the baby until it was reduced to a single bone. Photograph by Arianna De Marco

Other possible explanations for Evalyne's bizarre actions include her newness as a mother and the fact her baby was alive long enough to form a bond. (Read how cannibalism is surprisingly common in nature.)

In that sense, cannibalism may be the final, extreme expression of attachment to her baby, De Marco concludes.