Animal Mothers With Extraordinary Devotion

The longest egg-brooding of any animal known. Researchers returning to a rocky ledge about 1,400 meters down in Monterey Canyon found the same female wrapped around her clutch for four and a half years, in water of about three degrees Celsius. Across 18 dives she was never seen leaving the eggs or eating anything, and her skin grew loose and pale as she thinned. On the final visit she had gone and only empty egg capsules remained. Most female octopuses lay a single clutch and die at about the time it hatches, so this one long vigil was very likely the whole of her adult life's work.

A record for nursing among wild mammals. Chemical traces of milk laid down in the growth layers of orangutan teeth show that mothers can keep suckling a youngster for more than eight years: one Bornean juvenile showed no sign of weaning until 8.1 years, and a Sumatran one was still nursing shortly before its death at 8.8. The same teeth reveal that the young drift back to milk when fruit runs short in the forest, so a mother's supply is a fallback through lean seasons as well as an infant's food. Earlier field estimates had put the longest likely nursing at about seven and a half years, which is why the tooth study changed the picture. The evidence rests on a small number of museum specimens.

In the fish-eating resident orcas of the northeast Pacific, both sons and daughters stay with their mothers for life, and the mothering never really stops. Long-term records of the Southern Residents show that each surviving son cuts his mother's chance of having a new calf in a given year by more than half; researchers suspect she goes short herself while sharing food with a full-grown male. Mothering then carries on past menopause: post-reproductive grandmothers, who provide important leadership when the group forages on the salmon grounds, measurably improve their grandcalves' survival. Here maternal investment lasts a lifetime and visibly costs the mother.

Motherhood here starts with a pregnancy of about 22 months and a calf that can weigh up to 120 kilograms at birth, then widens into a herd of females who all keep watch over the young. The oldest mothers matter most. When researchers in Amboseli played recorded lion roars to 39 elephant groups, only those led by matriarchs of about 60 or older reliably picked out the greater danger of male lions, which can kill calves, and drew their herds into a defensive formation. Groups with younger leaders tended to underreact. It is a vivid field demonstration that an old female's experience helps keep her family's young alive.

A polar bear mother gives birth in a snow den to cubs weighing only about 0.6 kilograms, and while she is in the den she neither eats nor drinks. She nurses them until they are strong enough to leave, three to four months later, and by the time the family walks out onto the ice she may have gone about eight months without a meal. That fast is the striking part: everything the cubs grow on in those first months comes from the body she built up before denning. Nor does the care end at the den mouth. Cubs stay with their mother for just over two years, and some are nursed through their second birthday, though other mothers wean soon after the first.

Newborn pandas weigh three to five ounces, about 1/900th of their mother, which makes them among the smallest newborns relative to their mother of any mammal. Pink, blind and helpless, they depend on her for warmth and even for help passing urine and droppings. For the first weeks she does not leave the cub, even to eat or drink, cradling it against her body almost constantly. Zoo births, where this can be watched closely, have recorded mothers going days before stepping out of the den. The cub stays with her until it is about one and a half to two years old.

A mother that serves as her pup's raft. Sea otters raise their young at sea with no help from the males, and the female carries her pup on her belly as she floats on her back, nursing it there. Much of her effort goes on its fur. For about the first three months she grooms the pup extensively while its coat develops, because that coat traps the air that keeps it afloat and warm; a well-groomed pup bobs on the surface like a cork when she dives to feed. The pup stays dependent on her for about six to eight months.

As with all cats, the cheetah mother rears her cubs entirely on her own, and she does it on open plains where lions take cubs. What sets her apart is the hunting school. Once the cubs can follow her on hunts, she starts bringing her catch back alive, often something easy such as a newborn gazelle, and lets the cubs try to bring it down themselves. It turns a meal into practice, with the mother providing both the prey and the second chance. She keeps them with her until somewhere between about a year and 18 months, when the next pregnancy sends them off to fend for themselves.

The reptile that upends the idea of reptiles leaving eggs to fend for themselves. The female builds a mound nest of plants, then stays near it through an incubation of about two months, returning fast to drive off anything that threatens the eggs. When the hatchlings start calling from inside their shells, she opens the nest and carries them down to the water, eight to ten at a time, in the same jaws that make alligators so feared. The young then stay close to her, typically for about a year and sometimes for two or three, under her protection.

A tiny rainforest frog that runs a feeding round. Shortly after her eggs hatch, the mother carries the tadpoles piggyback, one at a time, to small pools of water such as the cups of bromeliad leaves, giving each its own pool. Then she keeps coming back. For about six weeks, until metamorphosis, she visits each tadpole and lays unfertilized eggs into its pool for it to eat. Those eggs pass on her toxins along with nourishment, and in experiments predatory ants preferred to attack tadpoles that had not been fed them. The father helps by guarding and watering the clutch, but the feeding is hers alone.

A legless, burrowing amphibian from Kenya whose young eat their mother's skin, and are meant to. After laying her eggs, the female grows a nutrient-rich, fatty outer layer of skin, and when the young hatch they scrape it off and eat it with specially shaped teeth. Researchers who filmed 21 brooding mothers found they lost about a seventh of their body weight in the week after hatching, with their skin cells turning up in the young's stomachs, so the cost is real. The authors suggested a fatty skin layer may be cheaper for the mother to make than eggs packed with yolk.

This southern African bird walls herself in. The female enters a tree cavity and narrows the entrance to a slit with mud, plant matter and droppings, then molts all her flight feathers, so she cannot fly while she is inside. There she lays and incubates the eggs and broods the chicks while her mate passes insects and regurgitated food through the slit. Only when her new flight feathers have grown, around sixteen days after the chicks hatch, does she break out. The arrangement depends entirely on the male's supply runs, but the mother is the one who gives up flight for the length of her confinement.

Maternal care is uncommon among insects, which makes the familiar garden earwig a surprise. The female digs an underground chamber, lays 30 to 60 eggs and guards them until they hatch, keeping them clean of fungi by licking them and gathering them up again if a mole or other burrower scatters them. The eggs hatch after about 70 days, normally in late winter, and the young stay in the safety of the chamber until they are larger, dispersing by the end of spring. Males usually return to the surface to forage and do not feed the young, so this is single motherhood in miniature, possibly under a stone in your own garden.

The most extreme entry here, and not for the squeamish. This velvet spider of the Negev Desert's dry river beds gives her offspring everything, in the most literal sense. After hatching, her dozens of young are fed for about two weeks on a clear liquid she regurgitates, made as her own organs break down in an orderly sequence. Then, with no attempt to escape, she is eaten: the spiderlings pierce her abdomen and drain her over the course of several hours. Biologists call it matriphagy, and in this species the mother's body is quite literally her final provision for her brood.