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Home › Ocean Creatures › Marine Life › Vertebrates › Snake Eels

Interesting Facts about Snake Eels

[Phylum: Chordata] [Class: Actinopterygii] [Order: Anguilliformes] [Family: Ophichthidae (serpent)]

More than two hundred (200) species of snake eels belong to the family Ophichthidae (meaning serpent-like worm eels). They are best known for their snake-like appearance and burrowing traits.

However, one of the most important facts about snake eels is that despite the serpentine aspect, they are not true sea snakes. They are fish and they lack any poisonous venom.

Snake Eels Habitat and Geographical Range

Ophichthidae exist in most tropical and warm temperate oceans around the world.

But, this large family of eels thrive in greater numbers in some regions, especially:

• Atlantic Ocean (including some rivers)
• Indo-Pacific region (most species found here)
• Parts of the Eastern Pacific
• The Caribbean Sea

Almost all snake eel species are bottom-dwellers living around shallow coastal waters that have lots of soft sand or muddy substrates.

Yet, the king snake eel (Ophichthus rex) and the manetail snake eel (Ophichthus urolophus) are two examples that inhabit the pelagic zone (free-swimming in open oceans).

Here's the kicker:

Despite their healthy populations, they are not easy to spot in the wild because they spend most of the day buried "tail-first" in the sand.

In general, they prefer to live in some of the shallower intertidal zones (e.g. less than 100 metres). But, sightings of snake eels deeper than five hundred metres (330 feet) are not unusual, such as the dark deepwater snake eel (Ophichthus aphotistos).

Snake Eel Characteristics and Behaviour

The key features of snake eels are the elongated, eel-shaped body (cylindrical) and the small eyes situated slightly above the pointed snout.

Having an adapted sharp bony pointed tail (caudal fin) means they can also burrow backwards into the sediment.

Even though some Anguilliformes have small pectoral fins, the ones that don't can create their protective burrows easier and faster.

But wait - there's more:

Two tubular nostrils point downwards from the head. This is important because they use these highly developed sensory organs (barbels) for hunting as they glide over the sea floor.

Most snake eels do not have "visible" scales, per se. Instead, their bodies are brightly marked with dark coloured bands, stripes, or spotted body patterns.

Despite the menacing and snake-like behaviour, and a strong relationship to their aggressive relatives moray eels, they are in fact harmless to humans.

That said, because they are "aposematic creatures", they often mimic some of the most venomous sea snakes to deter their natural predators (e.g. large fish, sharks, octopuses, and seabirds).

Snake Eel Size

The slender snake eel (Scolecenchelys macroptera) is one of the smallest worm-like eels, measuring about twenty (20) centimetres long (9 inches).

In contrast, the Bonaparte's snake eel (Ophichthus bonaparti) is one of the longest and some fully matured adults can reach 2.3 metres in total body length (more than 7 feet).

Interesting Fact: True sea snakes are reptiles with a paddle-like tail and they need to migrate to the surface to breathe. Whereas, snake eels (Ophichthidae) are fish because they have gills for breathing - instead of lungs.

What Do Snake Eels Eat?

Snake eels are nocturnal carnivorous predators and tend to be opportunistic feeders. They have a flexible diet and will eat various food sources.

So for example, after burying themselves rear-first inside a soft substrate, they wait for darkness with their head protruding to ambush their favourite prey.

The typical daily diet depends on their habitat, availability of prey, teeth type, and their size, but usually includes:

• Aquatic crustaceans
• Cephalopods (e.g. squids)
• Crabs
• Invertebrates
• Soft-bodied mollusks
• Polychaete worms (e.g. marine bloodworms)
• Slow-moving small fish

Pro Tip: Another section contains 10 facts about coral reef snakes and how their behaviour, diet, and reproductive process differs to snake eels.

Snake Eel Species List

How Do Snake Eels Reproduce?

Accurate information about the reproductive process of snake eels (family Ophichthidae) is quite limited. Moreover, breeding them in a captive environment has some unique challenges.

In the main, scientists have yet to study the mating rituals of these secretive creatures that live in buried habitats deep below the surface of the oceans.

Nevertheless, a lot of the expert research is based on comparisons to similar species of eels, especially moray eels (Muraenidae) and the freshwater eels that live in rivers, estuaries, and lagoons.

Therefore...

We know that when snake eels spawn in open water they do so through a process known as external fertilisation. Thus, they release eggs and sperm simultaneously (e.g. they are broadcast spawners).

Most eels produce flat-bodied, transparent "leptocephalus larvae" that drift in the water column for several weeks with other planktonic organisms. The larvae feed on organic debris called "marine snow" and eventually settle in a suitable domain on the ocean floor.

Snake Eel Threats and Predators

The IUCN Red List of Threatened Species assessed most of the snake eel species (Ophichthidae) in 2019 and they specified them as being of "Least Concern" (LC).

Besides being washed ashore by large storms, some of the contributing factors for a decline in certain vulnerable regions include certain types of human behaviour (e.g. coral reef destruction and degradation, bycatch, marine garbage pollution, warming seas).

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