Animal A Day!

Oxynotus caribbaeus The Caribbean Roughshark is a small species of shark that grows to a maximum length of about 1.5ft. Proof that not all sharks are gigantic terrifying man-eaters for sure! Caribbean Roughsharks hail from the Caribbean Sea and Gulf of Mexico, and they tend to live at depths of between 1400 and 1600 feet-- so no where near the surface! They have blunt noses, two dorsal fins, and no anal fin. They also have really unusual coloration-- darker grey or brown over most of their body, but light grey on the fins and head, with dark blotches. Because they live at those depths, they aren't studied a whole lot. We do know that they are slow moving predators, and they feed on small invertebrates and fish. These Sharks are most commonly seen when they get caught up in fighting nets. They show up occasionally as bycatch for bottom trawls. IUCN Status :  Data Deficient Location :   Caribbean Size :  Body Length up to 20in (50cm) Classification :  ...

Lamna nasus The Porbeagle is a large shark that is found in the cooler and temperate waters of the world's oceans. They can grow to lengths of around 12ft, and weigh over 500lbs! The name "Porbeagle" is a mysterious one. It's exact origins are unknown, though there are a few theories. One is that the name comes from Cornish terms for "harbor" and "shepherd." Another is that it is a combination of the words "porpoise" and "beagle," because of its porpoise like shape and dog-like hunting ability. Like many large sharks, the Porbeagles give birth to live young. They have up to 6 at a time, which take 8-9 months to gestate. At birth the young sharks are already more than 2ft long! Also like other members of their family, Porbeagles are effectively warm-blooded. They have vascular counter-current heat exchangers in their muscles which allow them to store up all the heat that they generate through fast swimming. They can make ...

Hybodus fraasi  (one of the many Hybodontiformes) The Hybodontiformes  Order is a sister group to the one that contains all of our modern Sharks, Rays, and Skates. It was first identified back in 1846, and since then species from five different Families have been uncovered. These prehistoric sharks were successful for a very, very long time-- they lasted nearly 200 million years and went extinct at the same time as the Dinosaurs-- 65 million years ago. There have been numerous species discovered within this order, and fossils have been found in places like China and Brazil. Interestingly, these animals lives in both saltwater and  freshwater. Unfortunately, that freshwater adaptation didn't save them from going extinct, and they began their decline during the cretaceous period. Status :  Extinct for 65 million years Location :   Worldwide Classification :  Phylum : Chordata -- Class : Chondrichthyes ...

Lissodus Normally when one thinks of prehistoric sharks, they imagine gigantic sea dwelling monsters like Megalodon-- huge  beasts with jaws the size of human beings that could devour anything and everything. Today's animal breaks that stereotype. Lissodus  was an entire genus of Sharks that lived on this planet for over 100 million years, spanning from the Triassic into the late cretaceous. They swam not in the oceans, but in fresh water, and their fossils have been found all over the world . So far there have been ten different species identified. Other differences between these sharks and their giant counsins? Lissodus was tiny . Especially compared to some of the super sharks. These guys measured only 6in long! They also had very interesting teeth, which they used for a specialized diet. Lissodus had flat teeth that allowed it to crush and eat clams. Status :  Extinct for 100 million years Location :   Worldwide Size :  Length up to 6in...

Pseudocarcharias kamoharai Our final Shark of the week is the Crocodile Shark, a small Mackerel Shark  that can be found in tropical  oceans all around the world. They are the smallest members of their Order, which also contains giants like the Great White and Megamouth Sharks. Crocodile Sharks grow to lengths of up to 3ft, and can be identified by their slender bodies, large eyes, long gill slits and small dorsal fin. Their large eyes help them to hunt at night, and they also posses a very large liver (up to 1/5 their entire body weight) that helps them to maintain a very neutral buoyancy. The species undergoes daily migrations, moving from deep waters during the day to more shallow hunting grounds at night. Crocodile Sharks are another one of those interesting Ovoviviparous species. And even more intriguing is that they have litters of 4 pups... two in each uterus . This is a trait not especially commo...

Somniosus microcephalus Today's Shark is one of my all time favorites-- they are just so unique! Greenland Sharks live farther north than any other Shark species in existence, swimming in the cold waters of Greenland, Iceland, and the North Atlantic. They can also grow to lengths over 20ft, allowing them to rival the Great White in size. Greenland Sharks are such unusual creatures. While many other Sharks species are quick moving, these icy giants swim very very slowly (only around 1mph!). They also spend a great deal of time not moving at all-- another name for these guys is "Sleeper Shark" since they are so frequently inactive. Don't let their slowness fool you! Greenland Sharks are still predators ! They feed primarily on fish, but are also able to snatch up unsuspecting sea mammals as well. Horse, Polar Bear, and Reindeer remains have all been found in Greenland Shark stomachs, though how much of that was carrion is not quite known. Greenland Sharks are...

Cladoselache species Today's Shark is the largest one that we have talked about so far, and it is also the oldest. Cladoselache  is the name of a genus containing eight different Shark species, all of which lived during the Devonian Period, around 370 million years ago. Sharks have been around for hundreds of millions of years, and the Cladoselache  Sharks are some of the best known of the ancient species. This is because many of their fossils were very well preserved in a formation near Lake Erie. Some of these fossils are so detailed that we know their stomach contents! These extinct sea creatures are interesting not only because they lived a very, very long time ago, but also because they had some interesting anatomical features . For one, they almost completely lacked scales. The only scales it had were found on the tips of the fins, and around the mouth and eyes. Secondly, these Sharks lacked "claspers"-- the reproductive organs that are ...

Heterodontus francisci Today's Shark is a very interesting looking species-- it has a very blunt head, prominent ridges over its eyes, two tall dorsal fins with spines, and a sandy colored body covered in dark spots. It also happens to be on the smaller side, though not as small as yesterday's Shark. Horn Sharks can reach lengths of around 3ft. You can find Horn Sharks swimming off of the western coast of North America, in a range that extends from Monterey to Baja. As juveniles they live in deeper sandy flats, and as adults they move closer to shore, swimming near reefs as shallow as 2m! The adult Horn Sharks have small ranges, and actually return to the same shelter after each night of hunting (they are nocturnal). They feed in small fish and a large variety of benthic invertebrates, including squid, crabs, and sea urchins. Interestingly, Horn Sharks aren't the greatest swimmers, and are quite slow and clumsy. They often use t...

Etmopterus perryi The 25th Annual Shark Week starts today, so obviously we need to learn about a Shark! Sharks have been very popular on Animal A Day, and we've learned about loads of them in the past ( a full list can be found here ). But we haven't yet talked about the smallest of all the sharks-- the Dwarf Lanternshark. Dwarf Lantersharks reach mature lengths of around 7in, and pregnant females can grow a small bit larger, topping out around 8in. They are an ovoviviparous species, and give birth to 2-3 pups at a time. Not only are these Sharks  very small , but they are also quite mysterious. They have only been found in a small section of the Caribbean, off the coat of Colombia and Venezuela. They swim at depths of between 900-1,400ft (274-426m), and are rarely caught or observed. So little is known about the biology and population size of these tiny sharks that they are listed as " Data Deficient ." They have no economic value ...

Isistius brasiliensis Today's animal is no joke! Though they only grow to be about a foot and a half long, they can do some really amazing looking damage to much larger sea creatures!  Cookiecutter Sharks  get their name from their relatively unique jaws and what they do with them. They have large, powerful sucking lips, a row of narrow teeth on the top, and a row of much larger, knife-like teeth on the bottom. Like other sharks, they regularly replace their teeth. However, instead of losing a single bottom tooth at a time, they replace the entire row at once! Old teeth are swallowed, giving the Cookiecutters a good source of Calcium. Cookiecutter Sharks attract their much larger prey using bioluminescent photophores (which grow bright green). The bigger sea creatures will go after the shark, but in a twist they will become the actual prey. The Cookiecutter will latch on with its mouth, spin its body around, and remove a perfectly circu...

Orectolobus maculatus If you look hard enough you'll be able to tell that today's animal, the Spotted Wobbegong, is actually just a very strange looking shark. In fact, all members of it's order are pretty goofy in appearance, and are collectively known as Carpet Sharks due to their mottled coloring and bottom-dwelling natures. Spotted Wobbegongs in particular have a greenish/yellowish/brownish coloration, covered in small, lighter outlined circles. These colors help them to remain camouflaged within the reef zones that they live. These sharks have a range that spreads across the continental shelf in the Indian Ocean and parts of the Pacific, and they are rarely found deeper than 350ft (110m). Crab, Lobster, and Octopus are three of the Spotted Wobbegongs favorite foods. They hunt at night, remaining very still and waiting for prey to come near. They do sometimes sneak up on their prey while hunting, but the wait-and-catch method is more common. One additional coo...

Isurus oxyrinchus Yesterday we talked about the Viviparous Lizard, a reptile that gives birth to live young. Today's animal, the Shortfin Mako Shark, also gives birth to live young and are Ovoviviparous. This means that their young are incubated inside their bodies, but inside an egg sac, not a placenta. Once the eggs hatch, the offspring practice Oophagy while still in the uterus. This means that they consume all of the unfertilized or underdeveloped eggs. Gestation can last as long as 18 months, and as many as 18 pups can be born at a time! Shortfin Mako Sharks also have the interesting distinction of being very, very fast . Their bodies are remarkable hydrodynamic, and they have been clocked at speeds of 31mph (50kph). Their is even some evidence that they can swim in fast bursts of 46mph (74kph)! They can also leap several feet into the air! One biological feature that allows them to move so fast is their circulatory system. It allows their body to be several deg...

Sphyrna mokarran Great Hammerheads are one of the many species of Hammerhead shark. They also happen to be the largest, hence the name. These Sharks have a massive range and can be found swimming in tropical and subtropical oceans worldwide. They also migrate seasonally , chasing the cooler waters during the summer months. Great Hammerheads live mostly near coasts, and are not typically found at depths of greater than 300m. Unlike many of the other Hammerhead species, Great hammerheads are solitary hunters. Stingrays are their favorite prey, but they also feed on bony fish and Cephalopods. Cannibalism has also been documented, as have attacks on humans. Interestingly, Great Hammerheads give birth to live young . After an 11 month gestational period, the female will give birth to as many as 40 pups! Illegal fishing, both targeted and bycatch, has hurt Great Hammerhead numbers in some areas. They are currently listed as Endangered by the IUC...

Another year, another Shark Week. And as the yearly television festival of all things Shark draws to a close, we'll learn about one more of these awesome predators right here. Galeocerdo cuvier Tiger Sharks are one of the largest shark species, and can attain lengths of well over 10ft. They are found in tropical and subtropical oceans all around the world, but are not commonly seen. The name given to these sharks derives from the banding pattern on their bodies. The coloring is more visible in juveniles, and fades as the sharks grow older. Tiger Sharks are notorious scavengers and are incredibly opportunistic with their feeding . This has led them to be responsible for more attacks on humans than any shark but the Great White. Tiger Sharks are also not at all picky about what they eat (unlike the Great White), which makes them less likely to let go of their human victims and swim away. New research also shows that Tiger Sharks take part in a practice called " Yo-...

Scyliorhinus stellaris The Nursehound is a type of shark known as a "Catshark." Also sometimes confusingly known as Dogfish, the Catsharks are characterized by elongated eyes and dorsal fins that are set far back toward the tail. Nursehounds are one of the larger Catsharks, and can be found in the Northeast Atlantic and Mediterranean. Molluscs and Crustaceans are favorites meals of the Nursehound, though they do feed on fish and even smaller Catsharks as well. They are a primarily nocturnal species, and spend the days hiding out in holes and rocks. Like most Catsharks, the Nursehound in an oviparous species. They lay two eggs at a time, but can produce up to 100 each year. Did you know that it takes nearly nine months for a Nursehound egg to hatch? Nursehounds are currently listed as Near Threatened, with their populations at risk due to habitat degradation and overfishing. IUCN Status :   Near Threatened Location :   Coastal Northeast Atlantic Ocean wa...

Bull Shark Phylum : Chordate Class : Chondrichthyes Order : Carcharhiniformes Family : Carcharhinidae Genus : Carcharhinus Species : C. leucas Length : 10ft (3m) Weight : 500lbs (226kg) IUCN Status : Near Threatened The Bull Shark gets its name from its short snout and aggressive attitude , which, combined with its toleration of fresh and brackish water, makes it one of the most dangerous sharks in the entire world. Bull Sharks have a widespread coastal range, and can be found off the coast of just about every continent except Antarctica. What is so amazing is that they are also found inland . Bull Sharks have be observed swimming up rivers and estuaries, and are even known to breed in freshwater. They have even been seen leaping up rapids to move further inland! There have also been a handful of shark attacks by these predators while several miles from the ocean. Bull Sharks give birth to between one and thirteen live young, and they reach sexual maturity at 8-10 ...

Nurse Shark Phylum : Chordata Class : Chondrichthyes Order : Orectolobiformes Family : Ginglymostomatidae Genus : Ginglymostoma Species : cirratum Length : 7.5-10ft (2.2-3m) Weight : 200-325lbs (90-150g) IUCN Status : Data Deficient The origin of the Nurse Shark's name is a bit shrouded in mystery. It might be a derivation of "Nusse," which is a name given to different types of "Catshark." It might also be taken from the Old-English Hurse, which refers to sea-floor dwelling sharks. It also might refer to the sucking sound that the sharks make while hunting. If those possible name origins didn't already give it away, the Nurse Shark is a bottom dwelling shark that has catfish-like whiskers. They can be found in both the Atlantic and Pacific oceans, in warm tropical and subtropical coastal water. Nurse Sharks are not harmful to humans, even though they can get quite large. The prefer to feed on bottom-dwelling invertebrates like shrimp, s...

( Image Source ) Phylum : Chordata Class : Chondrichthyes Order : Hexanchiformes Family : Chlamydoselachidae Genus : Chlamydoselachus Species : anguineus Length : Male 38-46in (97-117cm); Female 53-59in (135-150cm) IUCN Status : Near Threatened Frilled Sharks are elusive, deep sea sharks that were first observed on camera in their natural habitat back in 2004. Prior to that, they had only been seen after being caught in trawls (and even these was a very rare occurrences). Frilled Sharks can be found in oceans worldwide, though the distribution is patchy. The North Sea, areas around South Africa, and waters near Japan are some of the confirmed locations for the species. They live at depths of 500-1,000m, though are sometimes observed in shallower waters. Frilled Sharks have some pretty interesting anatomy. They are so named because of the "frills" that cover their six gill slits on each side. They have very eel-like bodies, and mouths filled with 300 trident-...

The New Jersey Man Eater might be a single shark, or it might be many different sharks. Either way, they were responsible for five attacks between July 1st and 12th, 1916.  These attacks resulted in four deaths and one injury. Summer at the Jersey Shore in 1916 was a hot one, with temperatures hitting over ninety degrees, forcing droves of people to to the cool ocean waters. On July 1st, Charles Van Sant, a 23-year-old on vacation from Philadelphia, went for a swim, going out about one hundred yards. Other swimmers saw a shadow approaching and called ou in warning, but Van Sant was unable to hear them. When he was about 50 feet fromt he shore, something grabbed at his legs, which caught the notice of Alexander Ott, a former Olympic swimmer. Ott dove out to help Van Sant, and carried him back to the shore, but it was too late for the young man. Both of his legs were badly mangled and he died on the shore. This was the first reported Shark Attack in New Jersey hi...

We've learned about the world's largest shark, so now lets move on to number two! Basking Sharks ( Cetorhinus maximus ) can be found in arctic and temperate coastal areas around the world. They are extremely migratory, following the plankton supply during the seasons, and can grow over 12m in length. Image Source That's right. Plankton. Like Whale Sharks, Basking Sharks feed off of tiny little creatures, rather than hunting and consuming larger prey as many of sharks do. They swim around with their large mouths open, ingesting whatever finds its way in. They then close their mouth and trap all of the food with help from gill rakers . All of the excess water is then expelled through their gills. They do have many teeth, but they are small and largely unused. Basking Sharks give birth to live young, making them ovoviviparous . Unfortunately, Basking Shark populations declined dramatically in the 20th century, due to overfishing. These Shrkas have extremely large liver...