Sacred Crocodile

Crocodylus suchus mummy

The Sacred Crocodile is an amazingly fascinating animal, because until very recently modern science was unaware that it was a unique species at all. Though there were some theories (based on skull shape) that date back to the early 19th century, the general thought was that all large Crocodiles in the Nile region belonged to the same species.

Well, as of 2011, we now know that there are actually two different creatures. Also surprising? They aren't closely related at all! In fact, the man who originally DNA sequenced a skin sample from a Sacred Crocodile kept running the test over and over because he thought something was wrong!

Nile Crocodiles and Sacred Crocodiles look very alike, but have different genetics, slightly different scute patterns, and very different behaviors. In fact, Ancient Egyptians knew all about the different temperaments of the Crocodiles that they lived among, and recognized that there were two different species thousands of years ago. The Sacred Crocodiles were more docile and tame, and were kept close to temples where they were considered, you guessed it, sacred. Additional evidence has even shown that Sacred Crocodiles were the ones mummified, not Nile Crocodiles at all!

The modern "discovery" of this second species could mean problematic things for the Nile Crocodiles. Their range may actually be smaller than estimated, and the Crocodiles skin trade will need to be carefully monitored and reevaluated. The exact population count of the Sacred Crocodile is unknown, but it is believed to be rather rare.

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IUCN Status : Not Listed
Location : Africa
Size : Length up to 16ft (5m)

Classification : Phylum : Chordata -- Class : Reptilia -- Order : Crocodylia
Family : Crocodylidae -- Genus : Crocodylus -- Species : C. suchus

Image : van Oudheden

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Gharial

Gavialis gangeticus

Meet the Gharial, one of the most interesting looking extant members of the Crocodile order. If you take a glance at the body, all seems normal. But the head? Gharials have incredibly narrow snouts, and the males have large bulbous appendages at the ends of theirs. The species actually gets its common name from that round appendage-- "Ghara" is an Indian word for a pot. It is believed that the males use the ends of their snouts for mating or for communication purposes.

Gharials have a range that extends across the Indian Subcontinent, and they are usually hanging about in the calmer areas or large rivers. Because their legs are so weak they seldom come on land-- only doing so to build nests or to bask.

It should come as no surprise then to hear that Gharials primarily eat fish. Their long snouts are excellent for fast, underwater lateral snatches, and their pointy teeth let them hold on with ease.

When it comes to breeding habits, the significantly smaller female Gharials live in harems that are watched over by an individual male. Mating takes place in December and January, and the eggs are laid in nests dug on shore a few months later. As will many Crocodiles, the female Gharials will help their new hatchlings crawl toward water, and will watch over them for several months.

Unfortunately, the odd looking Gharial is in a lot of trouble. They are listed as Critically Endangered, and are one of the most threatened Crocodilians out there. They nearly went extinct in the 1970s due to hunting and habitat degradation, but captive breeding and wild release programs have kept them going.. but barely.

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IUCN Status : Critically Endangered
Location : South Asia
Size : Length up to 20ft (6m)

Classification : Phylum : Chordata -- Class : Reptilia -- Order : Crocodilia
Family : Gavialidae -- Genus : Gavialis -- Species : G. gangeticus

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Dwarf Crocodile

Osteolaemus tetraspis

Meet the smallest living Crocodile, the appropriately named Dwarf Crocodile! These guys top out at lengths of only 5ft, which is pretty minuscule when you compare them to their larger Nile cousins. Those guys can grow to 16ft or more!

Dwarf Crocodiles are found in tropical west and central Africa. They live in ponds, swamps, and marshes, where they are most active during the nighttime hours.

When it comes to their personality and behavior, Dwarf Crocodiles are pretty timid and slow moving, but that doesn't mean they aren't still effective predators! They feed on all sorts of invertebrates and vertebrates alike, and will also consume carrion when available.

Mother Dwarf Crocodiles are very attentive parents. They build mounds out of decaying vegetation, which generate the heat needed to incubate the eggs. She will guard the mound until the eggs hatch, and then watch over her offspring for up to a year, as their small size makes them very vulnerable to predation.

Unfortunately, Dwarf Crocodiles are listed as Vulnerable. They aren't as well studied as their larger cousins, so the exact population status isn't as understood. It appears that hunting and deforestation are contributing to their decline.

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IUCN Status : Vulnerable
Location : Africa
Size : Length up to 5ft (1.5m)

Classification : Phylum : Chordata -- Class : Sauropsida -- Order : Crocodilia
Family : Crocodylidae -- Genus : Osteolaemus -- Species : O. tetraspis

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Morelet's Crocodile

Crocodylus moreletii

Allow me to introduce you to the Morelet's Crocodile, named for P.M.A. Morelet who discovered the species in 1850. This species, which lives in Central America, grows to lengths of up to 3m. They can be found in secluded freshwater swamps and marshes near the Gulf of Mexico.

Morelet's Crocodiles have been in trouble for a number of decades. They have been illegally hunted since the early 20th century because their skin can be used to make high quality leather. Habitat destruction has also hurt the species. Since the 1970s they have been monitored by the Crocodile Specialist Group, and their numbers have been improving.

Behavior wise, Morelet's Crocodiles are considered to be shy, which is why they prefer secluded habitats. They have the distinction of being the only New World Crocodile that they exclusively build mound nests for their eggs. These nests can be 3m wide and 1m tall, and the female will guard over their eggs until they hatch. She will then dig out her offspring and carry them to the water.

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IUCN Status : Least Concern - Conservation Dependant
Location : Guatemala, Belize, Mexico
Size : Length up to 9.8ft (3m)

Classification : Phylum : Chordata -- Class : Reptilia -- Order : Crocodilia
Family : Crocodylidae -- Genus : Crocodylus -- Species : C. moreletii

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Chinese Alligator

Chinese Alligator in Captivity

Did you know that there are only two species of Alligator in the entire world, and that they live in completely opposite hemispheres? The large American Alligator that we all know has a much smaller cousin, the Chinese Alligator, which grows to lengths of only about 5 ft! They are one of the smallest Crocodilians, and also one of the most rare.

Native only to China, the Chinese Alligator is Critically Endangered. It is estimated that there are only around 130 left in the wild! The severe drop in numbers is due to loss of habitat; the marshes that they live in are being converted to agricultural land. Luckily they have been bred successfully in captivity, and some have even been reintroduced back to the wild!

Chinese Alligators hunt at night and consume molluscs, fish, and other small water-living animals.

One interesting fact about these Alligators is that the female not only guards her 10-40 eggs every year, but she digs them out when they are ready to hatch and actually remains near her children throughout the winter.

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IUCN Status : Critically Endangered

Location : China
Size : Length up to 5ft (1.5m)

Classification : Phylum : Chordata -- Class : Reptilia -- Order : Crocodilia
Family : Alligatoridae -- Genus : Alligator -- Species : A. sinensis

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SuperCroc

Sarcosuchus imperator

Dinosaurs weren't the only massive reptiles to walk the earth millions of years ago, humongous Crocodiles were right there with them!

Meet Sarcosuchus, the "SuperCroc." This king of the middle Cretaceous was over twice the length of our modern Crocs, and had a head as long as a man is tall!

Sarcosuchus was first discovered back in the 1960s, but the remains were smaller and less complete. In 2000, paleontologist Paul Sereno located more complete, far larger fossils in the Saraha Desert. The name "SuperCroc" was born.

There is some argument over what SuperCroc ate. While some suggest that it may have gone after Dinosaurs, due to its massive size, others think they it probably just fed on fish. This is because its snout is similar to modern Gharials that eat fish almost exclusively.

SuperCroc went extinct around 110 million years ago, but as we all know, the Crocodile family lived on. SuperCroc is not a direct descendant of modern Crocodiles, but it did share many characteristics. These include the ability to create a wide range of sounds, and the upward placement of the eyes.

SuperCroc compared to other Crocodiles

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Status : Extinct for 110 million years

Location : Fossils discovered in what is now the Sahara Desert

Size : Length up to 40ft (12.2m), Weight up to 8.75 tons (7,900 kg)

Classification : Phylum : Chordata -- Class : Reptilia -- Subclass : Diapsida
Family : †Pholidosauridae -- Genus : †Sarcosuchus -- Species : S. imperator

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Black Caiman

Melanosuchus niger

The Black Caiman, named for its dark coloration, is the largest of all the Alligator species. Individuals as large as 19ft (6m) have been measured! These massive reptiles can be found stalking freshwater areas of South America.

Black Caimans have a wonderful senses of hearing and sight, which they use to track down and capture prey. They hunt primarily at night, and fish make up a large portion of their diet, but adults can also tackle much larger prey, including capybara, deer, and even livestock. There are some reports of human attacks as well.

Female Black Caimans are very attentive incubators. They build large nests during the dry season, and lay around 40 eggs within them. They eggs are then buried in the nest and guarded over for a period of 2-3 months. When it is time for the young Caimans to hatch, the mother digs them out. Because nests are often built close to each other, numerous young hatchlings can congregate in the same place for protection.

Illegal hunting during the mid 20th century has reduced the Black Caiman populations throughout their range. It is estimated that the population was reduced by 99% over the course of the century! The species is in recovery, but illegal hunting and habitat loss continue to pose a threat.

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IUCN Status :  Lower Risk, Conservation Dependent

Location : Amazon Basin

Size : Length up to 14ft (4.25m)

Classification : Phylum : Chordata -- Class : Reptilia -- Order : Crocodilia
Family : Alligatoridae -- Genus : Melanosuchus-- Species : M. niger

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False Gharial

I saw one of these interesting crocodilians at a zoo while I was on vacation last month, and its odd appearance blew me (and my family members who I went with) completely away. Tomistoma schlegelii is known as the "False" Gharial because it shares a similar snout to the "True" Gharials, but other morphological features place it within the family Crocodylidae. However, recent studies are showing that it might just be closely related to the True Gharials after all, and now the classification is a tad bit up in the air.

False Gharials are huge.. though not as huge as the other Gharials. They do however, regularly reach lengths of over 4 meters. Their snout is one of their most interesting features, because while the rest of their body is long and wide, their snout it quite thin. They live in Malaysia and Indonesia, and like all crocodilians, most of their time is spent in the water. Not a whole lot is known about their behavior. It is suspected that females build mound-nests to lay their eggs upon, but that the hatchlings receive no parental assistance.

False Gharials are considered to be harmless toward humans. The largest animals they are known to prey on are monkeys and small deer, though overall fish and crustaceans comprise a large portion of their diet. The slender snout that they possess helps them to capture these creatures, as it provides less water resistance when thrashing back and forth, and also allows them to probe into dens and burrows. Prey is swallowed whole.

False Gharials are an endangered species due to habitat loss, fishing, and the skin trade. Their are specimens in captivity (such as the one I got to see) but the total number of the wild population is probably around 2,500 adults, and they are very fragmented.

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American Alligator

Juvenile

To celebrate the 4th of July, and the fact that I just got back from South Carolina with more animal pictures than I know what to do with, we're going to talk about the American Alligator! There are only two extant species of Alligator, and the American is the largest. They live in freshwater swamps in the South Eastern United States and can grow up to 15 feet in length, though even larger specimens have been recorded. Alligators and other Crocodylians are very old species, with their ancestors appearing during the mesozoic era and surviving the great extinction that finished off the dinosaurs.


American Alligators are opportunistic predators, and will eat just about anything. There have been documented human killings, and since the statistics began in 1948, there have been 20 killings in the state of Florida. While that number does seem a bit chilling, overall humans are not a major part of the Alligators' diet. They eat birds, reptiles, mammals, insects and carrion. Alligators do not need to feed daily, and when the temperature cools down enough (below a around 73 degrees) they stop feeding all together and subsist on their stored up reserves. They can go for weeks at a time without feeding. American Alligators are very quiet hunters, moving towards prey with all but their eyes and nostrils submerged, and then springing forward in one fast movement to capture their meals. They are wonderful swimmers, but awkward on land. Alligators cannot chew their food, so they need to either consume meals small enough to swallow whole, or they have to tear off pieces of their kill.

Adult!

As far as reproduction goes, males attract females by bellowing. Interestingly, American Alligators do not have vocal cords. Despite this, the bellows can be heard over a mile away. Females build nests on land that protect and incubate her eggs, and she guards it vigilantly during the incubation period. Upon hatching, the young alligators alert their mother, who then has to dig them out of the nest. Juveniles remain with the mother for several months. In another interesting fact, a new study shows that female American Alligators choose to stay with the same breeding partner 70% of the time.

Feeding Time!

A question that I've been asked a handful of times is "What is the difference between an Alligator and a Crocodile?" Well, there are a few visible cues. First, the Alligator has a more broad, square head, while the Crocodile's is more pointy and triangular. The teeth can also be a big giveaway. The lower teeth of an Alligator fit snugly into their upper jaw, so only the top teeth might stick out. Crocodile teeth interlock, so both the upper and lower sets are visible externally. A less visible difference is the fact that Alligators stick pretty much exclusively to freshwater, where Crocodiles are more tolerant to salt water due to glands that allow them to filter out all of the salt. These are of course just a handful of difference between the two, but the jaw and teeth differences should be helpful in determining what you are looking at.

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