The toothy-grinned Nile crocodile is a distinctive creature of the
Nile valley. This species of crocodile, found in hot, steamy areas
of Africa, spends the majority of its days basking along river banks
with its mouth wide open. Mouth gaping is similar to the panting
of a dog; it helps a hot croc cool off. Mouth gaping also seems
to be an invitation to the Egyptian plover, or crocodile bird, to
clean the croc's teeth! Just how do crocs survive in the African
sun? Like other reptiles, the Nile crocodile is ectothermic.
If the temperature is high, the Nile crocodile slips into nearby
water, but if the air's cool, the croc sunbathes on a riverbank
to warm up. Its rough, scaly, water-tight skin prevents dehydration
on land, as well as loss of body salt when in water. During
the dry season, crocs travel considerable distances on land in search
As far as reptiles are concerned, crocodilians are tops when
it comes to parenting. These reptiles provide the most parental
care for their offspring. The female lays her eggs in a carefully
dug hole in the sand and mud on lake or river shores. For the next
three to four months she closely guards the nest, viciously attacking
any intruder, such as the egg-loving Nile monitor. When the young
are ready to hatch they make a chirping sound from the buried eggs.
The female then gently digs up and breaks open the eggs with her
mouth-releasing the 30 cm (12 in. ) long babies. The hatchlings
even get a free ride into the water. Mama croc scoops them up in
her mouth and carries them in her gular pouch to the river.
She will guard her babies for over a year after they've hatched.
Even though a female croc is a force to be reckoned with, many smaller
crocodiles fall prey to animals such as marabou storks, herons,
ibis, turtles, and catfish. Less than two percent of all Nile crocodile
eggs hatch and grow to maturity.
Crocodiles have not changed much over the last 200 million years.
However, that does not mean that crocodiles are not advanced reptiles.
Unlike other modern reptilians, crocodilians have efficient four-chambered
hearts like mammals. Their gular pouch blocks water so that they
can eat prey under water as well as on land. Their clawed feet help
them be excellent climbers and vertical pupils that open wide in
low light make them formidable nocturnal hunters.
not all. Crocs also have behavioral adaptations that make them more
advanced than snakes, lizards, or turtles. They are social animals
that work in groups to dig tunnels to cool off, and they care for
It is important to realize that the Nile croc is vital to the
riverine ecosystem. They have 66 sharp teeth that make them a top
predator in the food chain, help them to scavenge, and to eat barbel
catfish. If crocs were to vanish from the ecosystem, the barbel
catfish population could multiply enough to upset the balance of
the ecosystem. The catfish have voracious appetites and could wipe
out other fish species that are food sources for over 40 different
types of birds. The birds are needed because their droppings recycle
nutrients back into the system. Crocs are also scavengers that
feed on dead carcasses found along waterways, effectively cleaning
up the habitat. Without crocodiles, the Nile River and other freshwater
areas in Africa risk becoming watery deserts.
are few predators willing to tackle an adult Nile croc other than
another croc or people. And people have overhunted them for their
meat, skins, and other body parts. Agriculture and urban development
along the Nile have encroached on the croc's habitat and
completely changed parts of the river basin. Human impact has made
much of the wetlands unsuitable for its original inhabitants, endangering
many species as well as the crocodile. Although it is still endangered
throughout much of its domain, public awareness means hope.