Transcript:

Today on Animal Fact Files we’re talking about tadpole shrimp. These animals are also known as shield shrimp in reference to their shield-like shells. They are also sold as pets under the label “triops”. This label comes from the genus name for these crustaceans, but there are technically two genera in the tadpole shrimp order, so we’ll refer to these animals as tadpole shrimp for the remainder of this episode.

Tadpole shrimp are often referred to as living fossils due to their archaic-looking appearance, though finding one in the wild may not be an easy feat. Although tadpole shrimp live on every continent apart from Antarctica, the habitats in which they live may be fleeting. Tadpole shrimp are most commonly found in temporary water systems. Even a puddle that lasts only a few weeks may house these fascinating creatures. This is because tadpole shrimp eggs are made to last which we’ll be explaining in just a bit.

Tadpole shrimp aren’t actually shrimp, though they are crustaceans. They’re also not tadpoles, but they’re given this common name because they have a tadpole-like appearance while moving through the water. Tadpole shrimp are most commonly found in freshwater environments, and they can also live in brackish water. While ephemeral pools are their main environment, they may also be found in lakes and bogs. These are benthic creatures, meaning they spend their lives on the bottom of the water column. Here they’ll dine on detritus and small organisms. In large numbers, some tadpole shrimp species are considered pests in rice fields where their swimming can stir up sediment and knock over young rice seedlings, though generally speaking these animals are harmless.

In size, tadpole shrimp are able to reach four inches (10 centimeters) in length, but on average they measure less than half this. The current number of tadpole shrimp species is debated: some sources state around a dozen living species while others suggest more than three times this number. Tadpole shrimp are cryptic meaning different species may appear very similar to one another, their differences only perceptible through DNA sequencing. This, coupled with their sporadic appearance, means for now the exact number of tadpole shrimp species is unknown.

Tadpole shrimp are sporadic in their appearance as adults because their eggs survive for years, sometimes decades outside of the water. In this desiccated state, the eggs will endure harsh conditions like extreme temperatures or even being eaten! It isn’t until heavy rains come and fill temporary pools that the eggs hatch. Tadpole shrimp eggs hatch about one to three days after exposure to water. They develop quickly into adults, reaching reproductive maturity by two weeks of age. Tadpole shrimp may be hermaphroditic like snails, or they may have individuals with separate sexes. Tadpole shrimp eggs are carried for a short time on special leg patches of the adults. The eggs are then deposited in places such as moss. Hundreds of eggs will be laid. Some of the eggs will hatch immediately, others will hatch when the first rains come, others may require multiple hydrations before hatching. As adults, tadpole shrimp may only survive a few weeks, long enough to reproduce before their temporary home once again dries up.

For more facts on tadpole shrimp check out the links in the description. Give a thumbs up if you learned something new today, and thank you for watching Animal Fact Files.