Range: Northern Hemisphere

Habitat: Lakes, rivers, streams, swamps and more

Size: 6 mm long and 3 mm wide

Diet: Plant and animal material

Threats: Habitat destruction, likely mammals and birds

Lifespan: Two or more years

Transcript:

Today on Animal Fact Files we’re discussing river limpets. River limpets are also known as capshells. They're freshwater snails with white to grey oval shells that are relatively flat. They don't have that bubble shape like a lot of land snails, and their shell doesn't spiral. It has a bit of a raised area that leans towards the left and back of the snail’s body, but, fascinatingly, their internal anatomy is dextral– it leans to the right. Usually when snails have a left or right leaning shell, the internal anatomy follows suit, but not with river limpets. There are other freshwater snails known as river limpets (Ancylus fluviatilis), but this video is focusing specifically on the Acroloxidae family.

There are around 40 to 50 classified river limpets species, and they're disturbed throughout the Northern Hemisphere. They're largely found throughout the Palearctic region although there is at least one species living in North America as well. River limpets are not solely found in rivers. They also inhabit lakes, streams, canals, swamps, and more. They tend to prefer slow moving, cold water systems. River limpets are lung breathing snails, typically taking air from the atmosphere regardless of their largely aquatic lifestyle, however there are some species that live 3,000 feet (914 m) below the waves. Did you know there are lakes that go that deep? I didn't! These deep-dwelling species live in oil seeps and hydrothermal vents and obtain oxygen through a rudimentary gill-like structure.

The biggest threats these animals face are anthropogenic in nature. Many river limpet species are only found in single lakes. Disturbance or destruction of this habitat could mean the end of an entire species. They likely also face natural predators such as mammals and birds, although there's little information regarding these mollusc’s predators. In fact, there's not much documentation about their lives in general. At least one species is known to become the most reproductively active during the warmest parts of the year, but there's speculation these invertebrates reproduce year round.

River limpets are hermaphroditic meaning they have both male and female reproductive organs, however they do cross fertilize to produce offspring. They'll lay a handful of eggs in an egg capsule that gets attached to any surrounding surface. This might be a rock, a sunken log, or some aquatic vegetation. The babies hatch with tiny, smooth shells, and grow from there. River limpets likely live to at least two years of age, but there's still so much we don't know or fully understand. These are small snails, squeezing under rocks and other debris or hiding in aquatic foliage. They only reach about 6 millimeters long and half as wide! Like other snails, they use a radula to eat. A radula is a tongue-like structure that has tooth-like projections the snail uses to scrape plant and animal material off environmental surfaces.

For more facts on river limpets, 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!