Meet the oldest species on earth: the 250 million year tadpole shrimp

The tadpole shrimp (Triops cancriformis) is a very peculiar species. It is also known as dinosaur shrimp because it has been around for about 250 million years, which means it shared the earth with dinosaurs. Its odd shape and life cycle make it one of the most exciting species on the planet.

Tadpole shrimps are what is known as "living fossils," species that strongly resemble ─or are direct descendants─ of creatures we can only study by fossils. According to the specialized outlet Live Science, deep-sea fish coelacanths and horseshoe crabs are also called living fossils.

The tadpole shrimp's scientific name, Triops, is a description of its odd appearance: it has three eyes. Live Science explains that the species has two principal eyes and a third simple organ called an "ocellus eye" that helps it detect light. It also has a shield-like shell and a long flexible tail. It lives in shallow temporary ponds.

One of the most interesting facts about tadpole shrimp is their reproduction system. According to The Guardian, its eggs blow about in the wind waiting for the right moment to hatch out in a temporary pond. Some of its offspring hatch the following year if conditions allow, but others can remain dormant for another year.

Because they live in temporary ponds, the life cycle of a tadpole shrimp is relatively short (50 to 90 days). That is why the offspring grows to maturity in two or three weeks, becoming able to leave several batches of eggs behind before its habitat dries. The eggs then hatch when the pond forms again.

The Triops genus extends widely through the planet. According to The Guardian, they live in America, across much of Europe, Russia, and the Middle East. However, there are a few specific species in each region.

Live Science claims that scientists considered tadpole shrimp exactly the same animal as the 250 million-year-old fossils. However, a 2013 study of Triops DNA published in the journal PeerJ found that the current species evolved within the last 25 million years, which makes it a perfect candidate to study evolution.

A tadpole shrimp can eat 40% of their body weight in one day. It can eat almost anything that it can find in a temporary pond, The Guardian explains. That is why it grows up to three inches in length in just a few weeks.

Apart from being able to eat anything, tadpole shrimps are also easily eaten by almost any predator. According to The Guardian, "it makes a tasty meal for fish and many creatures that would inhabit permanent ponds." That is why it chooses temporary pools to reproduce and inhabit.

One of the main threats the tadpole shrimp faces is that humans often fill or destroy the temporary ponds they inhabit. This happens because these pools are regarded as useless. Climate change also threatens the environment in which these ancient creatures develop.

According to the International Union for Conservation of Nature, four species of Triops are endangered. They live in the Iberian Peninsula (Spain and Portugal) and are threatened by human activities such as development and agriculture, Live Science explains.

According to Wired, all tadpole shrimp species are great pet options for families that can not commit to a long-term animal companion. Their short lifespan and endurance make them very easy practice pets as well.

Since raising Triops can be perceived as a petting experience and a science experiment, Wired claims they are very easy to find. "Kits can be found in toy stores, science museum gift shops, and online." But make sure you buy from a company that grows eggs in a lab instead of harvesting them in the wild.

Most of the eggs come with raising kits. If not, Wired suggests a list of cheap common materials necessary to grow and nurture them. A desk lamp, a glass container or aquarium, and nutrients (if your kit does not come with them, you can use leaves).

Photo: YouTube

Only use a dozen or so eggs. Save the remainder for do-overs. Start in a small cup and then move them to a larger one as they grow. Avoid direct sunlight, and remember to use only non-chlorinated water.

Tadpole shrimp are an excellent tool for learning, as you can watch them change by the hour. Their peculiar habits, like swimming upside-down while they eat, and their unique appearance can make you appreciate them very quickly.