Romance is rare in the animal kingdom. Instead of wooing their partners before copulating, male ducks force themselves onto females, depositing genetic material with spiky, corkscrew penises. Then, there's tardigrade sex, which is less violent but not exactly heartwarming. Females lay eggs into a husk of dead skin. The male then ejaculates onto the eggs while stroking the female, and the whole process can take up to an hour.
But you can't talk about disturbing mating rituals in nature without mentioning snails. If you're unfamiliar with snail sexuality, you may assume that snail sex falls on the vanilla side: The mollusks, after all, are famous for being slow-moving and they don't even have limbs. But if you have the patience to watch a pair of snails going at it, you'll notice that things get interesting.
The first factor that complicates snail sex is their genitalia. Snails are hermaphrodites, meaning individuals have both a male set and female set of parts, and any two snails can reproduce with each other regardless of sex. But in order for a couple of snails to make little snail babies, one of them needs to take on the role of the female. That's where the love dart comes in.
The love dart, technically called a gypsobelum, isn't exactly the Cupid's arrow the name suggests. It's a nail-clipping-sized spike that snails jab into their partners about 30 minutes before the actual sex act takes place. The sliver is packed with hormones that prepare the receiving snail's body for sperm. Depending on the species, only one snail might release the dart, or they both might in an attempt to avoid becoming the female of the pair. You can watch the action in the video below.
For sex to be successful, both snails must insert their penises into the other's vaginal tracts at the same time. Both snails deposit sperm, and the strength of the love dart ultimately determines whether or not that sperm fertilizes their partner's eggs.
That's assuming the snail survives the little love-stab. In human proportions, the love dart is the equivalent of a 15-inch knife. Fortunately, snails are resilient creatures, and gastropod researcher Joris Koene tells KQED he's only ever seen one snail die from the transfer.
Snails also have a way of making it up to their partners after skewering them with a hormone stick. Their sperm deposit contains a dose of fortifying nutrients, something scientists refer to as a nuptial gift. It may not equal the energy expended during sex, but its enough to give them a small post-coital boost.
Good news for flying mammals: chubby little brown bats might be genetically resistant to white-nose syndrome, a fungal disease that’s killed more than 5.5 million bats since it was first documented in 2006 [PDF]. A new study in the journal Scientific Reports describes three genetic adaptations in the bats that could protect them from the pathogen.
Little brown bats (Myotis lucifugus), common in Canada and the eastern United States, are especially susceptible to white-nose syndrome. According to lead author Giorgia G. Auteri, a doctoral candidate at the University of Michigan, white-nose syndrome kills bats by disrupting their hibernation cycles.
“When they’re in hibernation in the winter, they’re not meant to be waking up. They’re supposed to be asleep,” Auteri tells Mental Floss. “But this fungus grows on them, and it causes the bats to keep waking up during hibernation. And because they’re waking up when they shouldn’t be, they’re running out of fat reserves too early.”
But while white-nose syndrome has devastated bat populations in North America, not all infected bats die from the disease—some recover. Auteri wanted to find out what made the survivors so special.
Auteri and her team compared the genetic makeup of nine surviving and 29 non-surviving little brown bats from northern Michigan. They discovered that survivors share three important genetic distinctions. “One is involved with fat metabolism,” she says. “And another is involved with regulating when the bats wake up from hibernation. And the third gene is involved in their echolocation ability, in their sonar for hunting insects.”
The results make sense, Auteri says. Because white-nose syndrome interrupts bats’ hibernation schedules, bats with genes that relate to more optimal fat storage (i.e., they’re fatter) and better hibernation regulation (i.e., they sleep longer) are more likely to survive the disease.
Auteri’s research could help scientists and conservationists find ways to preserve little brown bat populations. Besides being adorable, little brown bats also play an important ecological role as predators of insects like mosquitoes, moths, and other pests that are destructive to crops and forests.
A curious sloth says hello after members of the Jaguar Rescue Center reunited her with her baby.
Jaguar Rescue Center
In 2005, Catalonian primatologist Encar Garcia and her husband, Italian herpetologist Sandro Alviani, were living in southwestern Costa Rica when locals began to bring them injured animals in hopes that the two experts could save them. As word spread and more animals arrived, their property slowly transformed into a full-fledged rescue center. So they purchased the surrounding land and named their new organization the Jaguar Rescue Center (JRC), after one of their early rescues: a young, orphaned jaguar whose mother had been killed by farmers.
Today, the center covers nearly 5.5 acres of land near Puerto Viejo de Talamanca in Costa Rica’s Limón province. It can accommodate around 160 animals at a time, and is home to everything from spider monkeys to sea turtles (though, by law, staff members aren’t allowed to accept domesticated animals like cats and dogs).
While locals still bring injured and orphaned animals to the JRC, others are brought by tourists, the Ministry of Environment and Energy, the National Animal Health Service, and even the police, who confiscate animals that have been poached or illegally kept as pets.
Skye, a young howler monkey who recovered from electrocution.
Jaguar Rescue Center
The rescues are often victims of road accidents, animal attacks, environmental destruction, human interaction, or electrocution from exposed power lines. After the animals are rehabilitated, they’re released into La Ceiba Natural Reserve, a human-free (except for JRC workers) part of the forest where they can safely reacclimate to living in the wild. The JRC has cameras installed in the area to monitor the animals after their release and make sure they’re finding enough food.
Unfortunately, not all the creatures brought to the JRC recover from their injuries—in 2019, for example, 311 of the 749 rescues died [PDF]—so JRC staff members and volunteers understand just how remarkable it is to watch an animal regain its health and be successfully returned to its natural environment.
“There are so many amazing things about working for the JRC, but I think we all can agree that seeing a rescued animal make it through rehabilitation and be released is the best and most rewarding part of the job,” Torey, a JRC tour guide, tells Mental Floss.
Some thought-to-be-orphaned sloths are even released right back into the arms of their mothers. After recording the cries of a baby sloth, JRC staff will take the sloth back to wherever it was first found, play the recording, and wait for the mother to recognize the cries and (slowly) climb down from her leafy abode to reunite with her child.
Despite its partnerships with government agencies, the JRC doesn’t receive government funding. Instead, it relies on public donations and revenue from its visitor services. Find out more about how you can help below.
1. Donate money.
You can make a one-time or monthly donation that will go toward food, medical care, and supplies for the animals, or you can donate specifically to the JRC’s “Shock Free Zone” program, which insulates power lines and transformers that run through forests to prevent them from electrocuting wildlife.
2. Donate items.
Check out the JRC’s Amazon wish list to see which items are most needed—and what they’ll be used for, too. Examples include Pampers diapers for baby monkeys, snake hooks for safely rescuing snakes, and cans of worms to feed birds, opossums, and bats.
One of the most important products on the list is powdered goat’s milk, which staff members use to feed orphans of many mammalian species at the JRC.
“It has the most universally digestible enzyme compared to other milk,” Torey says. “Unfortunately, we do not have sloth milk, monkey milk, etc. readily available for the baby animals.”
3. “Adopt” an animal.
Diavolino, the Jaguar Rescue Center's "feisty little margay."
Jaguar Rescue Center
For $105, you can virtually “adopt” an animal at the JRC. Choices range from Diavolino, a “feisty little margay” rescued from the illegal pet trade, to Floqui, a whitish two-fingered sloth who was born with only one digit on each hand and foot.
4. Visit the Jaguar Rescue Center.
You can stay overnight at the JRC in one of its three visitor residences—La Ceiba House, Ilán Ilán House, or one of the Jaguar Inn bungalows—which offer a variety of amenities, restaurant service, and access to nearby beaches.
Whether or not you’re staying there, you can book a tour of the JRC, where you’ll get to explore the premises and even meet some of the animals. There are private, public, nighttime, and VIP tours, and you can find out more here.
5. Volunteer at the Jaguar Rescue Center.
If you’re looking for a more hands-on, potentially life-changing way to help Costa Rica’s wildlife, you can apply for the JRC’s four-week volunteer program or a position at La Ceiba Natural Reserve that lasts three to six months.
According to the website, JRC volunteers are housed in the Jaguar Inn and help with “a broad range of tasks, from doing the dishes and cleaning up after the animals ... to building and remodeling enclosures, or babysitting a new arrival to ease the stress of their new environment.”
La Ceiba volunteers, on the other hand, stay right on the reserve and do everything from monitoring captive and recently released animals to keeping the trails clear.