Coenobita clypeatus, which are also called land hermit crabs, are crustaceans that can be found in the western Atlantic. These crabs possess a head, body (cephalothorax), and abdomen that they protect by using shells. To maintain hydration, hermit crabs have gills on their large claw. While they can survive without food or water for extended periods of time, it is crucial for them to keep their gills damp for optimal health. Despite appearing harmless, hermit crabs possess strong claws and can cause harm if provoked, regardless of their small size.
In their natural habitat, hermit crabs usually travel in groups of approximately 25. However, when kept in captivity, they do not breed and instead mate on land near the sea. The female hermit crab then carries the developing eggs on her abdomen to either wet sand or a wet rock by the sea, where she deposits them. These eggs are subsequently carried out to sea by the tide. During this process, there can be anywhere from 1,000 to 50,000 eggs. In the ocean, these eggs undergo several molts and transformations as part of their growth process to acquire adult hermit crab characteristics. Once they reach the stage of adult larvae, they commence searching for a shell to inhabit.
As hermit crabs mature and find a suitable shell, they undergo a major transition by permanently moving to land. During this time, they grow by shedding their exoskeletons. It usually takes about ten days for their skin to harden after molting, which is crucial for regenerating lost legs. In the wild, hermit crabs can live for 25-30 years, but those in captivity typically have a lifespan of approximately 1 year.
Hermit crabs have an adaptable diet that encompasses a range of fruits such as apples, coconut, and grapes. They are opportunistic eaters and can consume nearly anything. It is essential for them to include salty foods in their diet. Additionally, they require fresh drinking water to ensure proper food consumption. By drinking from a shell, hermit crabs obtain the necessary calcium for their daily dietary needs.
Hermit crabs prefer to reside in temperatures ranging from 70 to 85 degrees. When confronted with cold or dry air, they tend to become inactive. Although they dislike moist and messy enclosures, hermit crabs thrive in dry tanks that have high humidity levels.
While visiting the zoo, I noticed some hermit crabs that were not moving. However, I learned that most hermit crabs are nocturnal and therefore tend to be inactive during the day but more active at night. It is important for the well-being of a hermit crab to exercise outside its cage as it can contribute to longer lifespans. Interestingly, hermit crabs are attracted to dark areas such as shady spots because they are creatures of the night. Although they enjoy exploring freely, hermit crabs usually return to familiar locations eventually. On average, these creatures live between 1-4 years.
In addition, I observed that larger hermit crabs do not show aggression towards smaller ones; typically, they only exhibit aggressiveness towards individuals of similar sizes.
Having previously owned a group of hermit crabs, I found them intriguing and enjoyed studying their behavior.
I chose the kangaroo as my vertebrate at the kangaroo site because their behavior was more active than the hermit crabs. While most of them were energetic, some were not. They engaged in activities like playing with toys, rolling in the grass, and basking under the sun. I picked the kangaroo because of their liveliness and my enduring fascination with their intelligence, speed, and jumping abilities.
Kangaroos, which are a type of marsupial mammal from the Macropodidae family, can be found in Australia, Tasmania, and New Guinea. There are 47 species of kangaroos. Most kangaroos have a herbivorous diet and live on land, consuming both grazing and browsing vegetation. Unfortunately, humans are the main threat to kangaroos as they hunt them for their meat and hides, which are commonly used in shoe production. Additionally, kangaroos compete with livestock for food resources.
In response to the increasing population of kangaroos in Australia by the late 20th century and the elimination of their natural predators like thylacines by Australian farmers, controlled hunting was implemented.
Kangaroos have long hind legs and feet, used for hopping and leaping. They also have thick tails which help with balance. When they forage, kangaroos often go on all fours. Their hind feet have four toes and are long and narrow. Their forelimbs are short and used like human arms, except the thumb is not opposable. Kangaroos have soft, wooly fur and some may have stripes on their head, back, or upper limbs. All kangaroos have a chambered stomach similar in function to ruminants like cattle and sheep. They regurgitate the vegetation they eat, chew it as cud, and then swallow it again for digestion.
Kangaroos have the ability to withstand long periods of time without drinking water. They accomplish this by digging deep wells, called kangaroo pits, which not only serve as a source of water for themselves but also benefit other animals in their habitat.
Kangaroos typically produce a single offspring each year. The joey, the newborn kangaroo, is born alive but in an underdeveloped state, measuring about 2 cm in length and weighing less than one gram. After birth, it climbs onto the mother’s body and enters her pouch. There, it attaches itself to one of the mother’s four teats, which expand to securely accommodate the joey. Over time, the joey becomes more active and gradually spends more time outside of the pouch. Between 7 and 10 months old, it completely leaves the pouch.
Female kangaroos become fertile shortly after giving birth. They quickly mate and conceive; however, within just one week of development, the embryo enters a dormant phase that lasts until the previous joey exits the pouch. Once this occurs, development resumes for the second embryo and approximately 30 days later, the kangaroo gives birth.
The three largest species of kangaroos belong to the genus Macropus. These species include the gray kangaroo, also known as M. giganteus or M. major; the wallaroo; and the red kangaroo, also known as M. rufus.
Found in open forests of eastern and southwestern Australia and Tasmania, the well-known gray kangaroo can have long hair and be silvery gray in coastal regions, but short-haired and dark gray inland.
The red kangaroo, which can be found throughout Australia’s interior grasslands, is the largest and most powerful species. A male red kangaroo can reach a head-body length of 1.5 m, have a 1 m long tail, stand 2 m tall, and weigh 90 kg.
With its impressive jumping abilities, a gray kangaroo can clear more than 9 m (30 feet) in a bound and reach speeds of 48 kilometers per hour.
Smaller and stockier compared to other species, the wallaroo can be dark gray to pinkish brown in coloration. It inhabits rocky areas all over Australia except Victoria.
All these large kangaroos travel in groups called mobs led by the largest male (“old man” or “boomer”), who asserts dominance through biting, kicking, and boxing.
