#elephantfish

When in doubt, follow your nose-- just like the elephantnose fish! This fish's 'nose', which is really an extension of the mouth, is covered in sensitive organs called schnauzenorgan. To navigate and find prey, the elephantnose fish emits weak electrical pulses from its tail; when they hit an object, the pulses bounce back to be detected by the schnauzenorgan, similar to echolocation!

Today's fish of the day is the bottle-nosed elephantfish!

The bottle-nosed elephantfish, also known as the eastern bottle-nosed mormyrid, freshwater dolphin fish, and scientific name mormyrus longirostris. Found throughout Western Africa!

These fish belong to the elephantfish superfamily, Mormyridae, which are known for their weakly electric ability. These fish give off pulses, which they can then read the electrical impulses sent by the muscle movement of nearby predators and prey. This is the same system used by the South American electrical Gymnotiforms order, which has fish such as the electric eel.

These fish are nocturnal, spending their nights hunting for food. Their diet is made up of small fish, lizards, eggs, and vegetation. They can grow up to 75cm, or 30 inches, although maternity is achieved at a size of 35cm.

The reproductive cycle of this fish is defined by the rainy season. These fish are poor swimmers, and during the rainy season these populations must harbor in areas of low current. This is when they breed. Male bottle-nosed elephantfish will swim in complex patterns to attract and court female elephantfish. Once they mate, and eggs are lain in vegetation, the males will protect both the eggs, and later the now hatched fry. These fish can live anywhere from 6-10 years, although there are claims of captive elephantfish living 15 years.

That's the bottle-nose elephantfish, everybody! I hope you had a wonderful time learning about them!

It's the last Wet Beast Wednesday of fresh-uary, the month where I only cover freshwater species. I started the month with a fish and am ending it with a fish as well. The elephant fish are a group of very bizarre-looking fish known for their long trunks. More than just looking weird, these little fish are potentially quite intelligent animals, much like their namesakes. Let's nose our way in and learn.

(Image: Peter's elephant fish, Gnathonemus petersii, in a tank. It is a long fish with mostly brown scales except for white stripes on the back half. It's dorsal and anal fins are large and near the rear of the body, giving it al almost arrow-shaped profile. The head is long, with small eyes and a very small mouth. Under the mouth sprouts a fleshy, trunk-like structure. End ID)

Elephant fish are also called elephant-nose fish and trunkfish, among a number of other names. They are members of the superfamily Mormyridae, though not every Mormyrid has the famous trunk. There are around 200 species, which can range in length from 5 cm to 1.5 m in the largest species, Mormyrops anguilloides (which does not have a trunk). The typical elephant fish is a smaller fish with a forked tail, large dorsal and anal fins located near the tail, small eyes, mouth, and gill openings, and a long, trunk-like protrusion emerging from below the mouth. In most elephant fish, the trunk is a modified lower lip and is muscular and somewhat flexible, but has no skeletal support. This type of trunk has the amazing scientific name of schnauzenorgan. Some mormyrids have alternatively developed extended jaw muscles and mouthparts that form a rigid trunk with a the mouth at the tip, but these trunks are usually shorter than the schnauzenorgans. The skin of Mormyrids, but especially the head and trunk, are covered with sensory pits known as ampullary organs or ampullae of Lorenzini. These kind of organs have evolved multiple times independently in several fish lineages and the variety that Mormyrids have are called mormyromasts. The purpose of these organs is to detect electric fields created by other living things.

(Image: Campylomormyrus elephas, an elephant fish. It has a very similar body structure to the first picture, but is black all over. Its trunk is actually an extension of the jaw and looks like a tube with a tiny mouth at the end. A small fleshy schnauzenorgan hangs from under the mouth. End ID)

In addition to sensing electric fields, elephant fish can create their own. They are considered weakly electric fish, because they actively generate an electric field around themselves, but the electricity they produce is not strong enough to be used as a weapon like in electric eels and torpedo rays. The ability to do this has also evolved independently several times. The electric field is generated by stacks of electricity-generating cells called electrocytes that are located in the tail. The use of the electrocytes creates an electric field that surrounds the fish like a bubble. when electric fields interact, they alter each other, and the elephant fish detects these alterations with its mormyromasts, altering it to the location of other organisms. Because all animals generate a weak electric field as a consequence of muscle movement and neuron activity, the elephant fish can essentially sense the location of animal whose electric field intersects with its. The trunk being covered in mormyromasts makes it extra sensitive to electrical fields.

(Image: Campylomormyrus elephas seen from the front, better showing the mouth at the tip of the trunk and the small schnauzenorgan hanging from beneath it. End ID)

To interpret all the signals it receives, the elephant fish needs a large brain. Their brain to body mass ratios are among the highest of any vertebrates, slightly higher than that of humans and their brain to body oxygen consumption ratio is the highest of any vertebrate, three times that of humans. Though their brains are simple in structure, they are capable of advanced cognition. In one test, elephant fish were shown to be able to recognize objects with one sense that they had only examined with another sense. For an example of this, humans can examine an object with their hands while blindfolded, then recognize it later when able to see. This is thought to be a rare ability in the animal kingdom, only found in intelligent mammals like dolphins, apes, and rats, and was formerly believed to require a cerebral cortex, something elephant fish lack. However, the fish were able to visually recognize objects they had previously only observed with their electric sense. It is currently not clear how they do this. There is also some evidence that elephant fish near each other can share information by linking their electric fields. If one fish senses something, it can transmit that information to all other nearby fish by altering its electric field. This could be highly useful in predator avoidance, where if one fish detects a predator, they all do. Elephant fish in captivity have also been reported engaging in play behavior (a sign of intelligence) and, like many fish, can recognize individual humans. I wasn't able to find any information on their memories, but fish with much smaller brains that use less oxygen have been shown to have at least several months worth of memory, so I would guess elephant fish can do the same.

(Image: a group of 4 blunt-jawed elephant fish, Campylomormyrus tamandua, in an advertisement for an aquarium company. They have the same body plan as Campylomormyrus elephas, but with a shorted trunk. Their bodies are striped with yellow and black. End ID)

Mormyrids are a highly successful group of fish, making up about 10% of all species of freshwater fish in Africa, where they are endemic. Mormyrids can be found in virtually every body of water in the continent, though elephant fish in particular tend to favor slower-moving, murky waters with lots of vegetation. While capable of using vision to examine their surroundings, electroreception is an even more valuable skill in murky water. Their electric sense allow elephant fish to navigate and hunt in water other fish would be blinded in. Elephant fish are carnivores, but their small mouth restrict them to very small prey, usually zooplankton, insect larvae, and other small invertebrates. Some trunkless species have larger mouths. Trunked species use their trunks to poke around in vegetation and sediment, looking for buried or hiding prey. The schnauzenorgans are reported to be flexible and can aid in carrying food to the mouth in a similar manner to an elephant's trunk. Hunting elephant fish have been seen doing a 'dancing' motion, which is believed to be used for reorienting themselves to better detect prey. They are active mostly during dawn and dusk and spend day and night hiding in vegetation to avoid predators. Mormyrid reproduction is understudied, but they have mating seasons that coincide with the rainy season. It appears that water acidity and soil content help trigger reproduction. Some species will leave the main waterways to mate in temporary pools created by the rain. Thy to not appear to provide parental care to their eggs or larvae. Elephant fish are known to be difficult to breed in captivity, limiting our understanding of how they reproduce.

(Cyphomyrus psittacus, a species of Mormyrid without a trunk. It has the same body plan as the above pictures, but its head is round and looks much more like a normal fish, except for a small, fleshy bulb below the mouth. It has silver scales. End ID)

Mormyrids are known to be vulnerable to pollution and are threatened by habitat loss, pollution, and climate change. As a group, they are doing well, though individual species may be threatened. Elephant fish have entered the pet trade due to their unique looks, with Gnathonemus petersii, Peter's elephant fish, being the most commonly found in personal aquariums. The same species is also highly used in laboratory experiments studying electrogenesis, fish intelligence, and bioelectricity. The difficulty of breeding them in captivity has led to a marked for wild caught fish. Some of the largest Mormyrid species are used for food.

Freshwater elephantfish!

After 15 million years the fluvial regions of central Africa have been changing in magnitude but their ecosystem remained similar to the time humans once stood on their shores, and as they have been gone for a long time their inhabitants kept evolving, no much of the fauna to the exception of the forest dwelling ones have changed, new species split from the older ones and other replaced previous ones. Fishes have been as fluid in change as the river they live, and so some have always tried to adapt with new strategies for their own survival or even their relatives.

In this case remarks a species of elephantfish (Mormyridae), a group of very diverse electric fishes from Africa characterized by their developed brains compared to other bony fishes, they have been experiencing further specialization with their intelligence that has changed their survival strategies, The Caretaker elephant-fish (Gnathoscalprum comifamilis) is a sample species of it, descendant of the Peters's elephant-nose fish (Gnathonemus petersii) it differs little of their ancestors morphologically with a average length of 25 cm long, though it has a more robust pointy chin and a larger tail electric muscle that help them to perceive their environment more than other species, although this is not what makes them stranger compared to other species.

There's nothing to be scared of about the Australian ghostshark-- it's neither a shark, nor a ghost! Known in Maori as makorepe, this species is actually a chimera; a cartilaginous fish related to sharks, rays, and skates. It's other common English name, the elephant fish, accurately describes the long snouts which they use to search for food along the ocean floor.

Today's fish of the day is the bottle-nosed elephantfish!

The bottle-nosed elephantfish, also known as the eastern bottle-nosed mormyrid,  freshwater dolphin fish, and scientific name mormyrus longirostris, is a mostly unknown fish. Found across Western Africa in Eastern flowing rivers, such as the Niger, Congo, and Senegal river systems. In and around cave systems with soft dirt bottoms across these deep freshwater rivers, where they hide in weedy vegetation. Populations migrate often, but unlike many fish in their family, not on a set schedule. Instead these fish migrate irregularly, as they are poor swimmers, and struggle in areas of high current, forcing them to move to avoid it during the rainy season. 

The elephantfish superfamily, Mormyridae, not to be confused with the marine elephant fish, which is a kind of chimaera. This family is known for being quite odd, as they have a unique sound processing system found in no other vertebrate, and the males are the only vertebrates to produce sperm cells without a flagella. They are also known for their weakly electric effect, which they use to sense prey and predators. Electric fields can be found in many different animals, most of which being aquatic. These are split into pulse type, and wave type, pulse type being characterized by long intervals of electrical discharge, and the wave type being made up of smaller connected pulses. The elephantfish family is known for their usage of pulse type electrical sensing, as they have a grouped retina that can only view red light. This, paired with their habit of living in areas of muddy or otherwise low visibility waters forces them to rely heavily on electrical sensing. This is what causes many to compare them to the Southern American electrical fish. The Gymnotiforms order, which forms the electrical organs by the exact same amino acid substitution, despite being separated by 60 million years of evolution. These organs being formed from the same muscle along the caudal tail. 

The bottle-nosed elephantfish is active at night, hunting for small invertebrates, lizards, eggs,weeds, and fish. These are found through the electrical organ. This can be broken into two parts, one of which being specialized cells along the fish, which are used to sense and read back information from electrical signals. The second part is the sender, which  sends pulsing signals from the tail, which then can read electrical signals sent by the muscle cells of moving animals. This is what allows them the find prey and predators! Other than this, the bottle nosed elephantfish is quite normal for their family. Named for the elongated and rounded body, with a large nose like structure. They can grow up to 75cm or 30inches, although maternity is achieved at 35cm in length. 

The reproductive and lifecycle behaviors of this fish are rather unknown, as it is particularly tricky to convince them to breed in captivity. In the wild, these fish are observed carrying as many as 10,000-70,000 eggs at a time, which will be laid during the rainy season, as the elephantfish populations are temporarily stuck in small areas on low current. These fish have been seen with courtship displays, made up of complex swimming patterns to attract females. After which eggs are lain in vegetation and the male will guard them. This behavior extends after the eggs hatch, with male bottle-nosed elephant fish remaining several weeks after the fry are born. These fish will go on to live anywhere from 6-10 years, although there are claims of captive fish living to 15, if kept particularly well.