The Green Sea Turtle

Extremely sensitive to changes in temperature, the green sea turtle (Chelonia mydas) is one of the thousands of species which faces extinction due to climate change. This endangered reptile has a vast range, inhabiting tropical and subtropical seas all around our planet. These turtles spend most of their time in seagrass beds, salt marshes and coral reefs around coastal areas. However, with rising sea temperatures, their natural habitat (particularly coral reefs) may soon disappear.

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Most adult green sea turtles are strictly herbivorous. Much of their diet consists of algae and sea grass. Their serrated jaw helps them gnaw through the vegetation. By biting off the tips of the seagrass, they help to keep the seagrass healthy and maintain ecological sustainability. Adult turtles have few predators – only humans and large sharks. In contrast, juveniles and new hatchlings feed a whole variety of coastal creatures, including crabs, small marine mammals and seabirds. The fact that these turtles play such a huge ecological role makes them a keystone species – their presence is vital to the survival and maintenance of coastal habitats.

Green sea turtles undertake lengthy migrations from feeding sites to nesting grounds throughout their life. Some swim more than 2,600 kilometres to reach their breeding grounds. These turtles return to the beaches on which they were born to lay their eggs. To lay their eggs, females haul themselves up onto the beach, dig a pit in the sand with their flippers and fill it with anywhere between 100 and 200 eggs. The female then returns to sea and the eggs will hatch within about 2 months.

Green Sea Turtle 3

Once the baby turtles have hatched, they face a perilous journey. During the darkness of the night, the babies instinctively head towards the sea. It is thought that they are drawn to the water by the ocean’s light. This comes with its own problem – the light produced by our cities is causing hatchlings to wander astray and towards our busy roads. If they manage to go in the correct direction, they still face predation from the aforementioned animals. It is estimated that only 1 in 1,000 hatchlings reach sexual maturity.

Classified as endangered by the IUCN (International Union for the Conservation of Nature), green sea turtles seem to have a bleak future. They are threatened by over harvesting of their eggs, hunting of adults, capture in fishing gear, plastic pollution, habitat loss and climate change. We are losing these creatures at an unsustainable rate because of our actions.

Green Sea Turtle

The incubation temperature of green sea turtle’s eggs actually determines offspring’s sex. Warmer temperatures are more likely to produce females whereas cooler temperatures are more likely to produce males. Increased temperatures caused by global warming are therefore producing more females than males. This threatens the genetic diversity and, ultimately, the survival of this species. A recent study conducted in the northern Great Barrier Reef found that of turtles from warmer nesting beaches, 99.1% of juveniles, 99.8% of subadults, and 86.8% of adults were female.

These threats not only endanger the survival of green sea turtles, but also the survival of entire ecosystems. There are many things we can do to combat the growing issue of climate change. Here are a few:

  1. Produce less waste – eat all the food you purchase and buy higher quality items that last for longer.
  2. Completely avoid air-freighted food – air freight emits more greenhouse gases per food mile than any other mode of transport.
  3. Reduce meat and dairy consumption.
  4. Make your voice heard – Homo sapiens are the reason for climate change but we can also be the ones who stop it.

 

Sources:

https://www.nationalgeographic.com/animals/reptiles/g/green-sea-turtle/

https://www.worldwildlife.org/stories/how-climate-change-is-turning-green-turtle-populations-female-in-the-northern-great-barrier-reef

https://www.worldwildlife.org/magazine/issues/fall-2015/articles/animals-affected-by-climate-change

https://www.worldwildlife.org/species/green-turtle

https://en.wikipedia.org/wiki/Green_sea_turtle

https://www.independent.co.uk/environment/green-living/food-miles-the-true-cost-of-putting-imported-food-on-your-plate-5333264.html#r3z-addoor

Hennessy, K., Wiggins, V. (2014) Animal Encyclopedia: The Definitive Visual Guide. 2nd edn. London. Dorling Kindersley.

The Gila Monster

Covered in pink and black bead-like scales, the Gila monster (Heloderma suspectum) is the largest lizard native to the United States. It is one of only two venomous lizards found in North America, along with Mexican beaded lizard. However, they are slow-moving and sluggish by nature so pose little threat to humans.

Gila Monster

These reptiles live in the deserts of southwestern North America, where they hunt insects and ground-dwelling vertebrates, including small mammals. Their name comes from Arizona’s Gila River basin – the area where they were first discovered. Gila monsters spend 90% of their time underground in burrows or rocky shelters, allowing them to stay cool in the desert heat.

Their oversized tails can be used to store large amounts of fat, letting Gilas to go for months without a meal. Unbelievably, these lizards may only consume as few as three big meals a year, and still maintain good health.

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You can clearly see the coloured beads that make up the Gila monster’s skin.

The Gila monster’s venom is a neurotoxin which would be extremely painful to humans, but there have been no reported deaths from being bitten by a Gila monster. Unusually for reptiles, the Gila monster does not inject its venom, instead it latches onto its victim and chews to allow neurotoxins to move through the grooves in their teeth and into the newly created wound. The most fascinating aspect of their venom is the proteins that it contains. A synthetic version of the protein exendin-4, derived from the Gila monster’s saliva, is used for the management of type 2 diabetes. Surprisingly, this protein has proved to be a highly effective treatment for diabetes, emphasising the ever-amazing wonders of wildlife.

 

Sources:

https://www.nationalgeographic.com/animals/reptiles/g/gila-monster/

https://en.wikipedia.org/wiki/Gila_monster

https://www.britannica.com/animal/Gila-monster

Hennessy, K., Wiggins, V. (2014) Animal Encyclopedia: The Definitive Visual Guide. 2nd edn. London. Dorling Kindersley.

The Nile Crocodile

The largest freshwater predator in Africa, the Nile crocodile (Crocodylus niloticus) is a formidable hunter with a great historical significance. They are widespread throughout sub-Saharan Africa, where they feed mainly on fish – like their Indian relative, the Gharial. However, these reptiles are opportunists so will attack almost anything unfortunate enough to cross its path, including zebras, wildebeest, small hippos, warthogs, bushpigs, porcupines, birds, and even other crocodiles. Once they have made a kill, they will rip off and swallow chunks of flesh, using the classic “death roll” to tear off particularly stubborn bits of meat.

nile crocodile 2

The Nile crocodile is possibly the second largest extant reptile in the world, after the huge saltwater crocodile. They can reach up to 6 metres in length, and weigh over 1000 kilograms in extremely rare cases. Though normally, adults don’t exceed 5 metres, and weigh around 500 kilograms. These crocs are quite sociable animals; sharing their basking spots and food with others. Their hierarchy is strict and determined solely by size and strength.

In the Maasai Mara National Reserve in Kenya, Nile crocodiles enjoy an annual feast. This reserve is famous for the annual migration of zebra, Thomson’s gazelle, and wildebeest to and from the Serengeti every year, known as the Great Migration. During this migration, these mammals must cross the Mara river – a river that is home to hundreds of hungry crocodiles. As huge herds of desperate wildebeest and zebra charge through the river, the crocodiles relish in the free buffet. These crocodiles have adapted, ingeniously, to exploit the delicious meals on offer.

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A Nile crocodile hunting a wildebeest in the Mara river.

Not only are Nile crocodiles superb predators, they also have an incredible past. Modern crocodiles have been around for about 80 million years, and the fact that they are still here today is a testament to their wonderful ability to adapt. In Ancient Egypt, the Nile crocodile was seen as the biggest and most dangerous predator; feared by many. However, the Egyptian people also had some admiration for these creatures – the Egyptian deity Sobek was based upon the crocodile. Mummified crocodiles and crocodile eggs have even been found in Egyptian tombs!

These reptiles were hunted close to extinction in the mid-1900s, but local and international conservation measures have helped populations to recover in most areas. Thankfully, their status is looking secure. The Nile crocodile has an undeserved reputation of being a vicious and ruthless man-eater, however incidents between people and crocodiles are rare. It is estimated that 200 people are killed each year by the Nile crocodile, a minuscule number when compared to the 1.25 million people who die in road crashes every year.

Nile Crocodile.jpg

Nile crocodiles are opportunists – they don’t actively hunt humans but will take an easy meal if presented with one. Crocodiles have been around far longer than we have. We should show them the respect they deserve.

 

Sources:

https://www.nationalgeographic.com/animals/reptiles/n/nile-crocodile/

http://www.krugerpark.co.za/africa_crocodiles.html

https://en.wikipedia.org/wiki/Nile_crocodile#Hunting_and_diet

https://en.wikipedia.org/wiki/Sobek

The Pig-Nosed Turtle

As you can probably imagine from their name, the pig-nosed turtle (Carettochelys insculpta) is quite an unusual looking reptile. To some, they may appear a little disturbing, but I actually find them rather adorable. Their odd features are surprisingly phenomenal adaptations to their aquatic habitat, and should be admired rather than mocked.

Pig-Nosed Turtle
Adorable? Yes….no?

The pig-nosed turtle is a freshwater species of turtle native to the lakes, streams, lagoons and rivers of Northern Australia and New Guinea. They are the only extant species in the family Carettochelyidae, which makes them incredibly unique. These reptiles are omnivorous, consuming a varied diet of crustaceans, molluscs, insects, and plant and animal matter. These nocturnal reptiles can reach up to 60cm in length, quickly outgrowing aquariums and fish tanks.

Pig-Nosed Turtle
A new born grasping the art of swimming.

For me, the most fascinating aspect of the pig-nosed turtle is their countless number of specialised adaptations. Unusually for freshwater turtles, the pig-nosed turtle has forelimbs modified as flippers, resembling those of marine turtles. This adaptation helps them ‘fly’ through the water, earning them the less common name of ‘Fly River Turtle’. In addition, their protruding pig-like snout is adapted for breathing air while submerged.  Its grey or olive coloured carapace (shell) lacks the hard scutes (plates) of other turtles and tortoises, and is instead more leathery in texture. This gives the pig-nosed turtle a more streamlined shape. These are just a few of the pig-nosed turtle’s superb adaptations.

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Most people have not heard of the pig-nosed turtle and some may never know about them. The pig-nosed turtle was recently added to the IUCN Red List of endangered species and their population is on the decline. One of their biggest threats is the international pet trade – thousands, sometimes even tens of thousands, of pig-nosed turtles are taken from their natural habitat and shipped off around the world to end up in aquariums and fish tanks, resulting in a rapid decline of their native populations.. Furthermore, they are threatened by demand for their eggs. With an undeniably unique appearance and array of wonderful evolutionary adaptations, the pig-nosed turtle deserves to be protected.

The Green Basilisk Lizard

Also known as the Plumed basilisk (Basiliscus plumifrons) or Jesus Christ lizard (I’ll get to that later), this omnivorous reptile is native to Central America and is part of the Iguana family. In their tropical rainforest habitat, the green basilisk lizard feeds on insects, small mammals, fruits, flowers and even other lizards. They have quite a few natural predators including: snakes, birds of prey and opossums so they need to be speedy.

Green Basilisk
A male green basilisk unwinding in the sun.

One of their most distinctive features is their bright green skin covered with small whitish-blue spots. Males can be uniquely identified by their three large crests: one on their head, one on their back and one on their tail whereas females only have the head-crest.

This cold-blooded creature is quite well known since they are able to sprint short distances across water – hence the alias ‘Jesus Christ lizard’ – which can help them swiftly evade predators. This impressive skill has only been made possible through centuries of delicate evolution. The green basilisk lizard has long toes on its hind legs with flaps of skin, giving them a larger surface area on the water thus reducing the pressure exerted. Therefore, they can travel for a reasonable distance before the force of gravity takes over, but not to worry, these lizards are superb swimmers and can stay under water for up to 30 minutes.

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Our lord and saviour: the green basilisk.

Their name is obviously derived from the basilisk – a legendary reptile also referred to as the serpent king. This fictitious creature was made up in Europe and was thought to cause death with a single glance. Although if you’ve seen the basilisk in Harry Potter, you’d probably agree that he was a little more intimidating than the green basilisk lizard. Nevertheless, this reptile is an undoubtedly fascinating creature.