Week Eleven: Hagfish

Common Name: Hagfish, Myxini

Scientific Name: Family Myxinidae

Domain: Eukaryota

Kingdom: Animalia

Phylum: Chordata

Class: Myxini

Order: Myxiniformes

Family: Myxinidae (this post covers all species; a primary genus of this family is genus Myxine.)

Description: I chose to put hagfish on this blog not because they are especially dangerous but because they are some of the most horrendous-looking creatures on this planet. Their bodies are long, fleshy, and whip-like, colored a dark pinkish-brown. Their mouths are jawless leeching suckers ringed by rasps that are similar but differ from teeth. This orifice is ringed by a set of sensory tentacles

Environment: Hagfish live on the seabed and in the twilit depths of the ocean. Here they encounter their already-decomposing food. The habitats they prefer are occur in very cold water, and are usually very dark, though still with some rays of sunlight. Hagfish crowd these environments, as they have a very high population. It is postulated that this is due to a low mortality rate as opposed to a high birth rate, because hagfish do not lay many eggs at a time.

Reproduction & Development: Hagfish hatch from one-inch-long eggs that occur in small numbers. At birth, they are hermaphroditic and for the most part miniature adults. As they develop they will only grow and form a definite sex, which may change over different breeding seasons. This process of foregoing a larval or nymph stage is known as “direct development”.

Nutrition: The main food source of the hagfish is polychaete worms and undersea carrion, especially the corpses of large marine animals which fall from higher levels of the ocean. Swarms of the creatures will latch onto gargantuan cadavers and rend strips of flesh using their tooth-like rasping suckers. Smaller swarms or singular hagfish eat decaying fish in the same way, and the animal is also known to capture and devour small marine invertebrates.

Week Ten: Platypus

Common Name: Duck-billed Platypus

Scientific Name: Ornithorhynchus anatinus
 
Fun Fact: The platypus is typically considered an adorable, if absurdly constructed, animal. However, the male of the species conceals a set of venomous spurs in his heels.

 

Domain: Eukaryota

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Monotremata

Family: Ornithorhynchidae

Genus: Ornithorhynchus

Species: O. anatinus

Description: When scientists were first presented with a platypus corpse, they thought that they had been given a taxidermist’s joke: a mammal’s body sewn to a duck’s bill. However, the platypus’s absurd anatomy evolved just like any other animal’s body: through natural selection. Its “duck’s bill” is extremely sensitive to aquatic vibrations and is used to detect underwater prey, and its short, waddling, webbed feet are used for swimming. The platypus is covered in thick, glossy brown fur.

Environment: The platypus is indigenous to Australia, and inhabits environments that include bodies of freshwater including rivers and lakes. The typical home of a platypus is a small burrow in the earth, often located in the banks of the lake or river which it frequents.

Reproduction & Development: The platypus belongs to a unique group of mammals know as monotremes, which lay eggs instead of giving birth to live young. They are still considered mammals, however, because they produce milk and are covered in fur. The young platypus is raised by its mother in her burrow after hatching from its egg, which usually spends ten days outside of the mother’s body before hatching. The young nurses for on average seven months after birth, and will become sexually mature in their second year of life.

Nutrition: The platypus mostly relies on freshwater invertebrates and fish for its food supply. It hunts by swimming underwater with eyes closed, relying only on the nerve endings in its bill for sensory perception of its prey.