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Which animals reproduce at the oldest age?
Motherhood is entirely possible at the age 74for some birds at least. A Laysan albatross (Phoebastria immutabilis) named Wisdom recently became the worlds oldest known breeding wild bird.According to the Pacific Region of the US Fish & Wildlife Service,, she returned to the Midway Atollor Kuaihelani in Hawaiianin December 2024 and began to interact with a new male partner. Wildlife officials then spotted what could be Wiscoms 60th egg. Get the Popular Science newsletter Breakthroughs, discoveries, and DIY tips sent every weekday. By signing up you agree to our Terms of Service and Privacy Policy.The egg should hatch sometime in February and is a good sign for birds that have been hit hard by highly pathogenic avian influenza (HPAI) or bird flu.Especially in the landscape of highly pathogenic avian influenza, its exciting to have a species that is still propagating this long when theyre facing some pretty incredible odds, Jennifer M. Mullinax, a research ecologist from the University of Maryland tells Popular Science.Wisdom is also not alone in her longer reproductive window, which is shared by other species of wild birds. Humans are really more of the outliers as far as living longer than we can successfully reproduce, and there are several species that have a much longer runway for having their young.Who reproduces for 1,000 years? Deep-sea spongesThey may look like an alien organism or some kind of giant plant, but sea sponges are part of the animal kingdom. While scientists are still learning more about their life spans, these deep-sea dwelling creatures can live incredibly long.A view of different species (sponges, crinoids, etc.) representing a deep ecosystem at 110m depth on September 24, 2019 off the French Guyana. CREDIT: Alexis Rosenfeld/Getty Images. Theyre colonial animals and some sponges are thought to have a lifespan as a colonial unit, in the order of thousands of years, Anne Clark, an evolutionary biologist and behavioral psychologist from Binghamton University in New York, tells Popular Science. And nobody says that theyre not reproducing in that time period.Sponges reproduce sexually to add to the colony and keep it going. Some deep-sea sponges can grow up to 12 feet long, all of it showing signs of life. With their biological drive in mind, Clark says it is entirely possible that some deep-sea sponges are reproducing for thousands of years.An elusive old sharkLike deep-sea sponges, greenland sharks (Somniosus microcephalus) live in very cold and dark waters and can live upwards of 200 years.Because theyre living in really cold water most of these species grow very slowly, says Mullinax. So theyre not really reaching sexual maturity for a very, very long time.Like some other shark species, they mate via internal fertilization and give live birth. However, unlike many other species that give live birth, their young is not attached to a placenta. Instead, their embryos survive off of a yolk sac. After reaching maturity, they potentially grow less than half an inch per year.Delaying implantationin bearsA young Grizzly bear cub watches the commotion in the valley below as its mother forages for food on June 14, 2024. in Yellowstone National Park, Wyoming. CREDIT: Jonathan Newton/Getty Images. For carnivorous land mammals, bears have a fairly long reproductive window. Depending on the species, a female will have a little about every three or four years after turning between four and six years old. During breeding, their bodies also have a mechanism to encourage the offsprings survival. They have a delayed implantation of the egg, where it is fertilized sometime during the summer months and will wait months to implant.A bear can be sexually mature, breed, and get pregnant. But then, if the conditions arent right, they can reabsorb the implanted embryo, because they dont have enough nutrients to bring them to term, explains Mullinax.The grandmother hypothesis: whales, elephants, primates, and moreWhile more rare, some animals other than humans can live long after their reproductive lives. These are often whales, elephants, or other matriarchal species where important knowledge is passed down to generations by females.The grandmother hypothesis is that somehow aged but non-reproductive animals are positively affecting the reproduction of a species just by their presence, explains Clark.A new born baby elephant is closely surrounded by its mother and aunts and uncles in the herd as they travel along the plains of the Kaudulla National Park. CREDIT: Dinouk Colombage/Moment via Getty Images. Older members of a group could share information critical to the animals survival. Studies have shown that older elephants and baboons can help younger members find water during times of drought.This is only open to certain kinds of animals that have long social lives, where their offspring are around and where dispersal doesnt break up families completely, says Clark.The R-Selectwhere every second countsOn the other end of the spectrum are the various species that live by a classic R-Select.In R-select species, theyre alive for maybe five days or five hours or five minutes, says Mullinax. They come into sexual maturity, they mate, they lay eggs, and they die.While mayflies in the larval stage can live for about a year, adult mayflies may only live for one day. Jellyfish and some rodents are also animals that have these short, reproductive driving lifecycles.This story is part of Popular Sciences Ask Us Anything series, where we answer your most outlandish, mind-burning questions, from the ordinary to the off-the-wall. Have something youve always wanted to know? Ask us.
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