Apr 26

You might not have it scheduled in your calendar, but today in in fact Alien Day! That’s right, a celebration of the films in which Sigourney Weaver, aka Ripley, battles some frankly terrifying extra-terrestrial creatures.

So we at Arkive had to jump at the chance to share with you our five favourite alien-like critters! These out-of-this-world species live right here among us, so there’s no need to blast off into space and cryo-freeze yourself for an encounter!

 Saiga antelope (Saiga tatarica)

These bizarre-looking antelope look like they’ve fallen straight off the set of Star Wars, but in actual fact can be found in the steppe grasslands of central Asia.

Despite their common name, these ungulates are actually thought to be intermediates between antelope and sheep. They prefer open areas free from dense vegetation where they run quickly (up to 80 miles per hour) to avoid predators such as wolves and humans

Large groups of saiga migrate southwards in winter, covering up to 72 miles in a day. The rut begins in late November and males gather groups of around 30 females in ‘harems’, which they aggressively defend.

During the rut, males’ noses swell up and the hair tufts below the eyes are covered in a sticky secretion. Males do not feed much during the rutting season, when they take part in violent fights that often end in death. The male mortality rate can reach 90 percent during this time, due to exhaustion.

Tail-less whip scorpion (Phrynichus jayakari)

The tail-less whip scorpion is spider-like in appearance and, as its common name suggests, it lacks a tail.

Tail-less whip scorpions differ from other arachnids (a group containing spiders and scorpions) in that they use only six of their limbs to walk, rather than eight, as the front pair are adapted to act as very long sensory organs. They may look like a bit creepy, but they are actually completely harmless and do not possess venom glands or a sting.

Tail-less whip scorpions are primarily nocturnal and emerge at night in search of food or a mate. They generally occur in tropical and sub-tropical regions, where they live under stones, leaves, bark or in rock crevices and caves.

Hairy angler (Caulophryne polynema)

The hairy angler is a deep-sea predator that looks like it is could have had a starring role in the nightmares of many pretty little reef fish whose parents warned them of the dangers of straying from the safety of their coral home.

The female is about the size of a football and its body is covered in long antennae, used to detect the movements of any nearby prey. The male is about a tenth of the size of the female, roughly the size of a ping pong ball. When a male encounters a female, it latches on and, over time, begins sharing the female’s blood supply, providing her with unlimited semen in response.

While we noted at the start that no spaceship was required for these sightseeing trips, the hairy angler lives at depths of over 1,000 metres, in the dark zone (we think it chose this for added dramatic effect), so you would probably need a very expensive submarine to pay it a visit.

Axolotl (Ambystoma mexicanum)

The axolotl is an unusual species of salamander which retains its larval features, such as gills, and remains aquatic throughout its life. They definitely look like a slightly more friendly alien creature who’d be more likely to sit down and play a board game with you than our previous guest creature, phew.

This real-life Pokémon mostly fails to undergo metamorphosis, but if its habitat dries up then this species can metamorphose into its adult form – magic!

Another out-of-this-world power the axolotl has is regeneration – X-men style! Instead of forming scar tissue when wounded, the axolotl can regenerate tissue at the wound site and even re-grow missing limbs.

The axolotl is native to the ancient water channel system of Mexico City, preferring deep brackish water with plenty of vegetation, but has been lost from most of its range and is currently listed as Critically Endangered on the IUCN Red List.

Coral

The tiny organisms that live inside corals, polyps, can live on their own but are mostly associated with the spectacularly diverse limestone communities, or reefs, they construct.

Coral polyps are tiny, translucent animals. These soft-bodied organisms are related to sea anemones and jellyfish. At their base is a hard, protective limestone skeleton called a calicle, which forms the structure of coral reefs.

They have to be on this list as they are so bizarre and unlike any other creature on the planet, many people don’t know they’re even an animal, or even sentient, mistaking the reefs they build for rock.

Corals eat by catching tiny floating animals called zooplankton. At night, coral polyps come out of their elaborate exoskeletons to feed, stretching their long, stinging tentacles to capture critters that are floating by. Prey are pulled into the polyps’ mouths and digested in their stomachs.

The majority of a polyp’s energy actually comes from tiny algae called zooxanthellae. The algae live within the coral polyps, using sunlight to make sugar for energy. This energy is transferred to the polyp, providing much-needed nourishment. In turn, coral polyps provide the algae with carbon dioxide and a protective home.

Don’t get us started on how they breed, or wage war on one another, as we could go on for hours on their otherworldly behaviour! But if you want to learn more about these amazing and highly endangered species, please check out our coral conservation topic page.

 

HAPPY ALIEN DAY!

Dec 16

Our natural world is full of mystery and wonder and one of the most mysterious natural phenomenon of all is bioluminescence. We’ve just created a new topic page to celebrate and explore this amazing adaptation that some animals possess.

Bioluminescence is the process by which living organisms produce their own light. Some organisms have organs that contain all of the necessary ingredients for light production, whereas others form symbiotic relationships with bioluminescent bacteria which they keep captive within a specially adapted appendage.

Most bioluminescent organisms are found in the deep sea below depths of 1,000 metres. Beyond depths of 1,000 there is absolutely no light from the sun and it is completely dark, therefore animals living at this depth have evolved to be able to produce light. There are a small amount of land-living organisms that produce light too, but this ability is much rarer outside of the deep-sea.

Check out these amazing bioluminescent species:

1) Murray’s abyssal anglerfish

Huge, blade-like teeth? Check. Unforgiving, angry expression? Check. Heading straight for you? It certainly seems that way! Anglerfish are arguably some of the world’s ugliest and most ferocious-looking animals. The females have a rod-like appendage on the top of their head, the tip of which contains bioluminescent bacteria. This is used as a lure to attract prey towards it, before it opens its huge mouth and engulfs its prey.

2) Ghost fungus

Until very recently, scientists were unsure as to why certain fungi species had the ability to produce light. It has recently been proven that it is a way to help them spread their spores as insects are attracted to the light, and when they pass by the gills of the fungus they are covered in spores. They then continue their journey through the forest, spreading the fungus’s spores as they go – how clever!

3) Flashlight fish

With this species, the clue for why it produces light is in its name. Underneath its eyes, the flashlight fish has organs containing bioluminescent bacteria, which glow and help the fish to see in the dark and also attract intrigued prey towards them – a classic example of curiosity killed the cat!

4) Glow worm

Despite being called a worm, glow worms are actually beetles belonging to the Coleoptera order. Female glow worms use their bioluminescence to attract males that are passing by and let them know that they are receptive to mating.

5) Ostracods

Ostracods are small crustaceans thought to exist in practically all aquatic environments on Earth and there are known to be over 33,000 species. Those living in the deep-sea possess the ability to produce light and use it to avoid being eaten. When a fish eats an ostracod it will produce a bioluminescent fluid which causes the fish to spit it straight back out again. This then alerts the whereabouts of the fish to larger predators, which could cause its eventual demise!

 

Want to know more about bioluminescence? Check out our shiny new bioluminescence topic page.

Browse the new bioluminescent species on Arkive and marvel at their amazing light-producing skills.

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