Range: Western North American coast

Habitat: Wet forests 

Size: Up to 10 inches (25 cm)

Diet: Detritus and fruit

Threats: Salamanders, snakes, birds, mammals, and more

Lifespan: Up to seven years

Transcript:

Today on Animal Fact Files we’re discussing banana slugs. These are some of the largest slugs alive today. They get their name from their color, though banana slugs aren't always yellow, or even yellow with brown spots. These invertebrates can appear brown, black, and even green– which are all also technically banana colors if you think about it! The moniker may also come from their shape. Banana slugs can reach upwards of ten inches (25 cm) long when fully extended. At that size, they could easily pass for the commonly farmed commercial banana species most folks associate with the word "banana."

Banana slugs are native to North America. They range from Alaska to central California inhabiting wet forests. They're active year-round, however, extreme cold will send them to burrow somewhere cozy and wait for warmer weather. When they are out and about, it's most frequently at night or during rain. It's not unheard of for these giant slugs to drop straight out of trees onto unsuspecting passersby! 

There are about a handful of banana slug species, though the specific number is in flux. These animals appear so similar to each other, the species can't be told apart by their appearance alone. No, it takes getting a little personal and examining their genitals to really know which slug is which. In fact, one species is specifically named for its long, slender penis. There's a lot more to discuss about these animals and their nether regions, so if that's not something you want to hear I recommend skipping to this time stamp.

Banana slugs, like other slugs, are hermaphroditic– they possess both male and female reproductive organs. In most cases, studies have shown that slugs prefer cross fertilization, meaning that instead of reproducing using only their own eggs and sperm, they mate with another member of their species to cross their gametes. In one study, however, banana slugs seemed to show a preference for self fertilization. Now, I fully admit this is personification, but one does have to wonder if the penis eating has anything to do with it. See, when banana slugs cross fertilize, they often finish by consuming each other's penis. Of course, observations exist of banana slugs eating their own penis after self-fertilization, so who knows? Maybe they're into it.

Outside of this unexpected behavior, banana slugs act like other slugs by breaking down decomposing material in their environment. They eat decaying leaves and carcasses and sometimes even feces. They'll also eat live plants like fruit! Some studies suggest they can help disperse the seeds of the fruits they consume, however, they're supposedly some of the slowest moving slugs alive today, so I'm not sure how far they actually take those seeds from their original point of origin.

Banana slugs lay eggs that hatch into babies that look like tiny versions of the adults. Their skin is translucent enough to see their internal shell. Did you know many slug species have shells? These are internal, reduced from an ancient external shell similar to a snail's. As they grow, this is no longer visible through their skin. 

A banana slug's body consists of the head with the tentacles that sense the surrounding environment: two on top for visual sense and two on bottom for smelling. Behind the head is the fleshy mantle with a hole they use for breathing with their single lung. The rest of the body is the foot which produces slime the slug uses to move around. The foot may have a keeled ridge along the back giving the animal the appearance of processing a spine, but slugs are invertebrates and thus have no spine to speak of.

Predators to banana slugs include salamanders who can eat slugs the same size as they are as well as snakes, birds such as ducks, and mammals like raccoons, however, the mucus these slugs produce helps protect them. When disturbed, the slug releases more slime than normal and this sticky substance can clog a predator's mouth. Many animals actually roll the slugs around in the dirt before eating them to get the mucus off! Humans even eat banana slugs by flaying them like a fish and frying them in butter. If they can avoid these threats, however, banana slugs may live to be five years old or even slightly older!

For more facts on banana slugs, check out the links below. Give a thumbs up if you learned something new today. Thank you to our Patrons SpikeSpiegel93, Dad, and everyone else for their support of this channel! And thank you for watching Animal Fact Files!