What do kayakers and river snails have in common? Keeled Ramshorn snail (Planorbis carinatus) that lives in rivers and lakes in Europe. (Gerhard Falkner/Hyun-tae Kim via EOL, CC-BY)
What do kayakers and river snails have in common?
Lexile

Both kayakers and river snails are animals who rely on freshwater. While for a kayaker, it's for recreation, for a snail it's about livelihood. Freshwater snails live underwater and feed on algae and other bits of aquatic food. Like kayakers, they depend on certain conditions of temperature, water flow and water quality for their activities.
 
Many of us have seen a land snail on a sidewalk or plant. On beaches, we have found shells that belong to marine snails, such as periwinkles, whelks and conchs. But freshwater snails are less visible and less well understood. Yet, freshwater snails are a really diverse group, with upwards of 4,000 known species, living on every continent but Antarctica.
 
What makes a snail a snail? It's an animal in the class Gastropoda. We think of snails as having shells, but slugs are actually snails as well, technically. What gastropods have in common is a muscular foot (gastropod = "stomach foot") that extends out from the bottom of their shell with the stomach and other organs coiled above. Most gastropods use the foot to move around, whether creeping, swimming or burrowing. Slime secreted by special foot glands helps smooth their way forward.
 
Many human activities affect snails by polluting or otherwise altering the habitats they live in.  Freshwater snails are particularly vulnerable because they live in patchy environments. Imagine the view from above a landscape dotted with ponds, lakes and streams. Snails are not exactly speedy, and if the freshwater they live in becomes uninhabitable, they may not have the ability to move to a new setting.
 
Damming, mining, draining and the myriad of other changes to freshwater ecosystems have taken a toll on freshwater snails. The impacts show in the dozens of species that have gone extinct and dozens more at risk of extinction. While we might wonder about the significance of losing any single species of snail, collectively they sustain food webs in which they play roles as ecosystem engineers - breaking down dead materials, cycling nutrients and maintaining water quality. 
 
Zoologist Ellen Strong studies freshwater snails in an effort to understand their biodiversity and ecosystem needs. Learn more about her work on these cryptic animals in the "Smithsonian Science How" webcast on Thursday, May 11. During How Humans Impact Freshwater Snails (airs at 11 a.m. and 2 p.m. EDT on the Q?rius website), Ellen will take you on a journey to her field sites while answering your questions live. You can also get teaching resources to use with the webcast.

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CRITICAL THINKING QUESTION
How can something as large as a kayaker and as small as a snail have anything in common?
Write your answers in the comments section below


COMMENTS (5)
  • nathanm14-ste
    5/05/2017 - 01:39 p.m.

    The two aren't similar. The article only gives a few reasons of how the tow are alike, and it's annoying. Just tell me about snails, i don't need to know some bogus reason of how they're two peas in a pod. It is fun to pour salt on unsuspecting snails like some sort of god.

  • peytonw-cel
    5/10/2017 - 09:58 a.m.

    They both depend on certain conditions of temperature, water flow and water quality for their activities. Kayakers want to have good water quality so they can kayak and snails also want good water quality so they can live. They both rely on freshwater as well. They both are against pollution as well, because pollution can affect both kayakers and snails. Water flow is important because kayakers want good water flow to guide their kayaks downstream, and snails need good water flow so more nutrients flow.

  • charlesj-bur
    5/11/2017 - 05:43 p.m.

    Both don't have anything in common, except for the fact that freshwater snails eat kayaker's.
    I can relate because I'm really short and I have big and tall friends.

  • siennac-kut
    5/29/2017 - 10:33 a.m.

    They both have roles in the ecosystem. They both depend on water.

  • jocelyf-cot
    8/16/2017 - 11:12 a.m.

    Although a large kayaker and a small snail are different in size, they have some things in common. Some things they have in common are they both rely on freshwater, and they are both gastropods meaning they use their stomach as a muscular foot. The text states "Both kayakers and river snails are animals who rely on freshwater." The text also states "What gastropods have in common is a muscular foot that extends out from the bottom of their shell with the stomach and other organs coiled above. Most gastropods use the foot to move around, whether creeping, swimming or burrowing. Slime secreted by special foot glands helps smooth their way forward." This evidence shows that although kayakers and snails are different in size, they still have some things in common.

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