6 animal fathers who go the distance
Popular Science...
In the animal kingdom, fatherhood exists on a spectrum. Some species like grizzly bears or lions will leave after mating and never really interact with their offspring again. Others do everything from keeping eggs warm solo to carrying their young in their mouths and even giving birth.
“By the male investing in offspring it increases the chance of their survival, and specifically the survival of his genes,” Karen McDonald, an educational specialist at the Smithsonian Environmental Research Center tells Popular Science.
“Male-only parental care is rare in mammals and vertebrates, but it’s surprisingly common in ray-finned fish (over 50 percent of families), with many species caring for large broods of their offspring from different females. In birds, male-parental care is less than one percent of the species.”
Here are some of the unique ways that some animals experience fatherhood.
Seahorses and their little ‘fry’
Seahorses are the unofficial poster species for animal fatherhood. While the female produces the eggs, the male is the one who gets pregnant. After mating, the female transfers her eggs to a brood pouch on the male’s tail for him to fertilize.
“Crazy cool fact, the seahorse brood pouch is really like a placenta,” McDonald explains. “It does the same things, with respiratory gas and waste exchange, salinity regulation, nutrient supplementation, and immune protection. Essentially it’s what is confirmed as a ‘vertebrate pregnancy.’”
The male then cares for the eggs for roughly two to four weeks and before releasing the babies–called fry. Depending on the species, they can have anywhere from five fry up to 2,000 at one time. Having as many babies as possible is critical since only about one in 200 will survive.
Water bugs and their egg glue
Some aquatic animals like giant water bugs (aka toe biters) make use of a staple found in human dad’s tool chest—glue.
“Eggs are laid by the female onto the males’ dorsum or back using a protein-based egg glue,” McDonald explains.
The water-resistant secretion helps the eggs stay in place. Depositing the sperm directly helps the male insect ensure paternity.
Three-spine stickleback and hidden nests
Like giant water bugs, male three-spine stickleback fish (Gasterosteus aculeatus) also make use of glue, but with a twist. They use a sticky secretion from his kidneys called spiggin to cobble together marine debris and algae into a tunnel-like nest.
“The male spiggin or kidney glue that is used to glue the nest has genetic plasticity, allowing for nest construction based on the environment they are in,” McDonald says. “The male can actually tune the chemistry of the glue to match the water chemistry, so that it holds it together better and can adjust to the environment.”
Once he’s ready to breed, his belly turns red and he performs a special zig-zag dance for the female. She will then take a look at the den he built and deposit the eggs. She leaves after fertilization and he will then stay to protect them.
Greater rheas and their single dad skills
If seahorses are the poster species for males who can give birth, greater rheas (Rhea americana) are a model for stay-at-home dads. These large, flightless birds will build nests for their mate’s eggs, take care of all the incubation, and then rear the chicks alone and keep them safe.
“Rheas are the largest birds in South America and among the largest birds in the world,” Sara Hallager, Curator of Birds at the Smithsonian’s National Zoo and Conservation Biology Institute, tells Popular Science. “Adult greater rheas don’t have many predators but large cats (cougar, puma, jaguar) native to their range can take down an adult. Chicks and juveniles are the most vulnerable, but once a rhea reaches adult size, they are usually pretty safe.”
Arapaima and their amazing mouths
Native to the Amazon River, arapaima are one of the largest freshwater fish in the world and don’t have many natural predators. For their tiny babies, also called fry like seahorses, it’s a whole different world. To keep them safe, arapaima dads suck their young into their mouths when they sense danger. They then swim to a safe area and release them.
“Arapaima will build a nest and females can lay anywhere from 20,000 to 50,000 eggs,” Rebecca Sturniolo, Curator for Amazonia and American Trail at the Smithsonian’s National Zoo and Conservation Biology Institute, tells Popular Science. “Both parents will defend the nest.”
These big fish also breathe air at the surface of the water, to help them survive in habitats with lower levels of oxygen.
Golden lion tamarins and their teaching skills
Golden lion tamarins (Leontopithecus rosalia) are small monkeys found in the trees of Brazil’s Atlantic coast. After birth, their young will spend a few weeks with their mother to nurse. Then, it’s all about dad. Baby golden lion tamarins will cling to dad and ride along wherever he goes.
“Babies are learning the sights, sounds, and smells of the forest,” Kenton Kerns, a curator and biologist at the Smithsonian National Zoo and Conservation Biology Institute, tells Popular Science. “They’re learning what ‘safe’ feels like, what ‘danger’ is, how to react to other animals or other golden lion tamarins. They’re learning what adult tamarins eat by watching dad, how they move, where it’s best to sleep.”
Golden lion tamarins were critically endangered until 2003, when they were upgraded to endangered. When they were brought to the zoo during the 1970s, the Smithsonian team and Brazilian researchers collaborated to figure out how much paternal care these primates need.
“Zoo staff kept the dads in the with the babies, which was a bit unorthodox with primates at the time,” says Kerns. “That change allowed a boom of babies in zoos and led to the eventual reintroduction of zoo-born golden lion tamarins to Brazil.”
Happy Father’s Day!
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