In the sea there is a huge number of animals, some of them totally unknown to most of society. One of them is the sea flea, a tiny crustacean that seems to be a great nuisance for some beach bathers, since it is usually believed that it causes bites and skin irritation. If when we are on the beach we feel or see a bite or wound, it is very important that we urgently go to a medical center to have a diagnosis and start the most appropriate treatment, since there are a variety of animals that can cause us these injuries or we can hurt ourselves with rocks, abandoned waste, etc.

Do sea fleas bite or not?
Although it is frequently attributed to the bites suffered by bathers on the beaches, sea fleas are not dangerous to the health of the human being. They cannot be responsible for these bites because they do not bite or bite people, because human skin is not included in their diet nor do they usually defend themselves like this.
If you have suffered a bite on the beach, it is important that you discard these animals as responsible: it has probably been another marine animal or an insect that inhabits the sand or plants of the seashore.
What are sea fleas?
Sea fleas, whose scientific name is Talitrus saltator, belong to the group of thallids and have these characteristics:
- They are animals of the crustacean group and very active.
- The thallids are part of a family of approximately 300 species.
- They live on sand or wet land, so it is common to see them on the beaches.
- They are a very important part of the diet of numerous seabirds and fish.
- They reach a length of between 20 and 25 mm.
- Despite their small size, sea fleas are capable of jumping more than 20 cm.
- They are a grayish-brown color.
- Its body is compressed in the dorso-lateral direction and is divided as follows: a head, a thorax or pereon and the abdomen or pleon. These last two parts are smooth and segmented.
- The eyes of sea fleas are black and rounded.
- Their head is large in proportion to the rest of the body, and they have a very different face from the rest of crustaceans.
- They have drooped mouthparts and a palpate-free jaw. Its antenna I is significantly shorter than the peduncle of its antenna II, which is more robust and has a flagellum with a serrated appearance.
- Females of sea fleas have shorter and less robust antennae than males, although their antenna II is longer than antenna I.
- In the thorax, they have 7 pairs of appendages, the first two being modified in the form of similar gnatopods in females and males. Of these appendages, the first two have an oval and long base. The first is robust despite being simple and has an elongated V artifact. As for the second, the final artejo is in the form of a mitten. The appendages of the abdomen, that is, the marching legs or pereopods, are prickly and robust. The telson is slightly wider than it is long and contains numerous spines.
Nocturnal activity of sea fleas
Sea fleas have a nocturnal activity that lasts from 6 to 8 hours in the intertidal zone, with a maximum of between 1h and 3h regardless of the state of the tide. It is a very curious behavior and that is due to two purposes:
- Prevention of the burial area of sea fleas from being completely flooded during the next tide.
- Maintenance of humidity, as it allows them to do their vital functions. It is a necessity as for the rest of the crustacean species.
What sea fleas eat
Sea fleas feed on algae and decaying organic waste. In this way, they carry out a task of cleaning the grains of sand of the beaches one by one. The care of their offspring is very particular, since the females ingest the offspring so that they feed on their body and, in this way, a sufficient source of food is ensured so that the offspring develop and can continue looking for food. It is an act that they do instinctively.
By feeding on algae and organic waste accumulated on the seashore, these fleas become vulnerable animals, being a perfect food for gulls and other species.
Now that you know sea fleas well and you know that, although they are compared to fleas, it is not because they bite or bite, but because of their size and their jumps, we recommend you read about the bites of other animals that inhabit the beaches and the sea and that can bite us by accident. Here you can learn about the Sea Urchin Sting, the Jellyfish Sting and the Spider fish Sting.