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Monthly Archives: May 2011

Elephant

Elephant

Elephants are the largest land-dwelling mammals on earth. They are brown to dark gray in color and have long, coarse hairs sparsely covering their bodies. They have very thick skin that keeps them cool. Elephant trunks serve as another limb. A fusion of the nose and upper lip, the trunk may contain more than 40,000 muscles that help the elephant use it to gather food and water. They also have large ears and thick tree-trunk-like legs to support their great weight.

Fast Facts

Height: 5-14 ft at shoulders (males); females of all subspecies are smaller than males.
Length: Up to 30 ft trunk to tail.
Weight: 6,000-15,000 lbs (males).
Lifespan Up to 70 years.

There are two distinct species of elephants: the African elephant (genus: Loxodonta) and the Asian elephants (Elephas maximus). There are a number of differences between the two species – overall size, ear size, tusks and shape of the back and forehead among others.

Of these two species, African elephants are divided into two subspecies (savannah and forest), while the Asian elephant is divided into four subspecies (Sri Lankan, Indian, Sumatran and Borneo). Asian elephants have been very important to Asian culture for thousands of years – they have been domesticated and are used for religious festivals, transportation and to move heavy objects.

Diet

Staples: Grasses, leaves, bamboo, bark, roots.
Elephants are also known to eat crops like banana and sugarcane which are grown by farmers. Adult elephants eat 300-400 lbs of food per day.

Population

At the turn of the 20th century, there were a few million African elephants and about 100,000 Asian elephants. Today, there are an estimated 450,000 – 700,000 African elephants and between 35,000 – 40,000 wild Asian elephants.

Range

African savannah elephants are found in savannah zones in 37 countries south of the Sahara Desert. African forest elephants inhabit the dense rain forests of west and central Africa. The Asian elephant is found in India, Sri Lanka, China and much of Southeast Asia.

Behavior

Elephants form deep family bonds and live in tight matriarchal family groups of related females called a herd. The herd is led by the oldest and often largest female in the herd, called a matriarch. Herds consist of 8-100 individuals depending on terrain and family size. When a calf is born, it is raised and protected by the whole matriarchal herd. Males leave the family unit between the ages of 12-15 and may lead solitary lives or live temporarily with other males.

Elephants are extremely intelligent animals and have memories that span many years. It is this memory that serves matriarchs well during dry seasons when they need to guide their herds, sometimes for tens of miles, to watering holes that they remember from the past. They also display signs of grief, joy, anger and play.

Recent discoveries have shown that elephants can communicate over long distances by producing a sub-sonic rumble that can travel over the ground faster than sound through air. Other elephants receive the messages through the sensitive skin on their feet and trunks. It is believed that this is how potential mates and social groups communicate.

Reproduction
Mating Season: Mostly during the rainy season.
Gestation: 22 months.
Litter size: 1 calf (twins rare).
Calves weigh between 200-250 lbs at birth. At birth, a calf’s trunk has no muscle tone, therefore it will suckle through its mouth. It takes several months for a calf to gain full control of its trunk.

Climate Change and Other Threats

Habitat loss is one of the key threats facing elephants. Many climate change projections indicate that key portions of elephants’ habitat will become significantly hotter and drier, resulting in poorer foraging conditions and threatening calf survival. Increasing conflict with human populations taking over more and more elephant habitat and poaching for ivory are additional threats that are placing the elephant’s future at risk.

Defenders of Wildlife is working through the Convention on International Trade in Endangered Species (CITES) to maintain a ban on the sale of ivory as well as on regulations that govern worldwide elephant protection.

Legal Status/Protection

  • Endangered Species Act (ESA): The African elephant is listed as threatened. The Asian elephant is listed as endangered.
  • IUCN Red List: The African elephant is listed as near threatened. The Asian elephant is listed as endangered.
  • CITES: Elephants are listed in CITES Appendix I, except in Zimbabwe, Botswana and Namibia where the African elephant is listed as an Appendix II species.
  • African elephants are also protected by the African Elephant Conservation Act, whose purpose is to perpetuate healthy populations of African elephants.
 
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Posted by on May 31, 2011 in Animal in North America

 

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Dolphin

Dolphin

Dolphins are highly intelligent marine mammals and are part of the family of toothed whales that includes orcas and pilot whales. They are found worldwide, mostly in shallow seas of the continental shelves, and are carnivores, mostly eating fish and squid. Dolphin coloration varies, but they are generally gray in color with darker backs than the rest of their bodies.

Fast Facts

Size: The familiar bottlenose dolphin is around 8 feet (2.5m) long and weighs between 440-660 lbs (200-300kg).
Because the forty species of dolphins are so diverse, they range in size. The smallest of the dolphin species, Maui’s Dolphin, is around 4 feet (1.2m) long and weighs around 90 lbs (40 kg). The largest dolphin species is the orca, or killer whale. Male orcas grow to about 25 feet in length and weigh about 19,000 pounds.

Lifespan: Most dolphins live long lives. The bottlenose dolphin can live over 40 years, and the orca can live to be 70 or 80!

Diet

Dolphins consume a variety of prey including fish, squid and crustaceans.

Population

It is difficult to estimate population numbers since there are many different species spanning a large geographic area.

Range

Most species live in shallow areas of tropical and temperate oceans throughout the world. Five species live in the world’s rivers

Behavior

Dolphins are well known for their agility and playful behavior, making them a favorite of wildlife watchers. Many species will leap out of the water, spy-hop (rise vertically out of the water to view their surroundings) and follow ships, often synchronizing their movements with one another. Scientists believe that dolphins conserve energy by swimming alongside ships, a practice known as bow-riding.

Dolphins live in social groups of five to several hundred. They use echolocation to find prey and often hunt together by surrounding a school of fish, trapping them and taking turns swimming through the school and catching fish. Dolphins will also follow seabirds, other whales and fishing boats to feed opportunistically on the fish they scare up or discard.

Reproduction
Mating Season: Throughout the year, though in some areas there is a peak in spring and fall.
Gestation: 9-17 months depending on the species. When it is time to give birth, the female will distance herself from the pod, often going near the surface of the water.
Number of offspring: Usually one calf; twins are rare.
As soon as the calf is born, the mother must quickly take it to the surface so it can take its first breath. The calf will nurse from 11 months to 2 years, and after it is done nursing it will still stay with its mother until it is between 3 and 8 years old.

Climate Change and Other Threats

As the seas and oceans warm, dolphins are being seen more frequently in colder waters outside their historic ranges. Due to the rapidly rising oceans temperatures, the dolphin’s primary food sources are seeking deeper cooler waters. Scientists are concerned that the dolphins will have difficulty adapting as quickly as necessary to find new feeding grounds to sustain their populations. Some dolphins that live in areas where rivers and oceans meet, known as brackish waters, are also losing habitat as ocean levels are rising due to global warming.

Dolphins also face a number of other threats including marine pollution, habitat degradation, harvesting, low frequency sonar, entanglement in fishing gear, boat traffic.

Reasons For Hope

Dolphins are one of the most iconic species of the marine world. With their playful nature and high intelligence dolphins have captivated the hearts of people of all ages from all over the world. Due to their popularity, many countries are researching and monitoring dolphins to ensure their survival. In April 2009 biologists working in Bangladesh found a thriving population of 6,000 Irrawaddy dolphins, which were thought to be critically endangered, off the coast as part of a monitoring project started in 2004.

Legal Status/Protection

  • Endangered Species Act (ESA): The Chinese River dolphin, the Indus River dolphin, and the orca/killer whale are listed as endangered under the Endangered Species Act.
  • CITES: All species of dolphin are protected under CITES. The snubfin dolphin, amazon River dolphin, Indo-pacific humpbacked dolphin and the Atlantic humpbacked dolphin are listed in Appendix I; all other dolphins are listed in Appendix II.
  • Dolphins are protected under the Marine Mammal Protection Act.
 

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Diamondback Terrapin

Diamondback Terrapin

Named for the diamond-shaped growth rings on its top shell, the diamondback terrapin (Malaclemys terrapin) a turtle native to the eastern and southern United States.

Fast Facts

Length: 7.5 inches (females); 5 inches (males).
Weight: 1.5 lbs (females); 0.5 lbs (males).
Lifespan: 25-40 years.
The diamondback terrapin is light brown, gray or black on top with a bottom shell that ranges from yellow to olive in color.

Diet

Diamondback terrpains consume fish, snails, worms, clams, crabs and marsh plants.

Range

The diamondback terrapin is found along the Atlantic Coast of the eastern United States from Cape Cod to the Florida Keys and west along the Gulf Coast to Texas

Behavior

The diamondback terrapin is believed to be the only turtle in the world that lives exclusively in brackish water (containing some salt, but not as much as ocean water), habitats like tidal marshes, estuaries and lagoons. Most terrapins hibernate during the winter by burrowing into the mud of marshes. Although diamondback terrapins live in tidal marshes, estuaries and lagoons, their preferred nesting sites are sandy beaches.

Reproduction
Mating Season: May through July.
Gestation: Around 60 days.
Clutch size: 8-12 eggs.

The gender of diamondback terrapin offspring is determined by temperature – a higher nest temperature produces more females while a lower nest temperature produces more males.

The hatchlings emerge from August to October and are completely on their own. Only 1 to 3% of the eggs laid produce a hatchling, and the number of hatchlings that survive to adulthood is believed to be similarly low.

After hatching, some young remain in the nest during the winter although most emerge and enter the nearest body of water.

Climate Change and Other Threats

The diamondback terrapin is threatened by habitat destruction, road construction (terrapins are common roadkill) and drowning in crab traps.

Climate change is also poised to bring major changes to the terrapin’s habitats and life cycle. By the end of this century, sea level is projected to rise between 2.25 feet under a low emissions scenario and up to 3.25 feet under the highest emissions scenario.

Due to land subsidence in the Northeast, the effect of the rise will seem about 10 to 20% higher than the actual. Salt water incursion into brackish tidal marshes will alter their character and potentially make large areas saltier than the terrapin can tolerate. Storm surges and beach erosion threaten their preferred nesting habitats. And higher temperatures on nesting beaches could skew the sex ratios of offspring.

Legal Status/Protection

  • Endangered Species Act (ESA): Diamondback terrapins are a species of concern.
  • IUCN Red List: Near threatened.
  • The diamondback terrapin is officially protected by several individual states.
 
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Posted by on May 30, 2011 in Animal in North America

 

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Desert Tortoise

Desert Tortoise

The desert tortoise (Gopherus agassizii) is a large herbivore and the official reptile in the states of California and Nevada. No other tortoise in North America shares the extreme conditions of habitats occupied by the desert tortoise.

Fast Facts

Height: 4-6 inches.
Length: 9-15 inches (shell length).
Weight: 8-15 lbs.
Lifespan: 50-80 years.
The desert tortoise has a high domed shell, or carapace, that is greenish to dark brown in color. Its front limbs have heavy, claw-like scales and their flat shapes are well-designed for digging.

Diet

Varies throughout the desert tortoise’s range. A desert tortoise’s diet may include herbs, grasses, some shrubs and the new growth of cacti and their flowers.

Population

The number of desert tortoises has decreased by 90% since the 1950’s. Recent estimates indicate that there are about 100,000 individual desert tortoises existing in the Mojave and Sonoran deserts.As late as the 1950’s the desert tortoise population averaged at least 200 adults per square mile. More recent studies show the level is now between 5-60 adults per square mile.

Range

The desert tortoise can be found in the Mojave and Sonoran Deserts of southern California, Nevada and Utah. They inhabit semi-arid grasslands, desert washes and sandy canyon bottoms below 3,500 ft

Behavior

The desert tortoise is able to live where ground temperatures may exceed 140 degrees F because of its ability to dig underground burrows to escape the heat. It is one of the most elusive inhabitants of the desert, spending up to 95% of its time under ground to escape the heat of the summer and the cold of winter. They live in burrows which they dig. These can be 3-6 feet deep. They will spend November through February in a torpid or dormant state in their underground burrows.

Their most active time is in the spring when they will forage for food. During the hottest, driest periods of the year the tortoise conserves water already stored in its body. This is especially important in the hot, dry Mojave Desert summers. Winter hibernation aids in minimizing water loss.

Much of the tortoise’s water intake comes from moisture in the grasses and wildflowers they consume in the spring. To maximize the utilization of infrequent rainfall, tortoises dig catchment basins in the soil, remember where these are, and may be found waiting by them when rain appears imminent. Water that reaches the bladder is not lost to the system but can be drawn upon as needed. Adult tortoises may survive a year or more without access to water.

Reproduction
Mating Season: Late summer to early fall.
Gestation: 10-12 months.
Clutch size: 4-6 eggs.
Females do not breed until they are 15 to 20 years old. Survival of juveniles is low: only 2-3 per 100 hatched may live to become adults.

Climate Change and Other Threats

The desert tortoise is very sensitive to human disturbances, and this has led to the decimation of many of its populations throughout the desert southwest. Increased urban development in the deserts of California and other states have fragmented and reduced suitable habitat. Certain fatal diseases appear to be spreading among tortoise populations. Poaching, the use of off-highway vehicles within tortoise habitat and crushing by automobiles have also continued to threaten tortoise populations.

Ravens cause significant levels of juvenile tortoise predation in some areas of the Mojave Desert with more prevalence of human disturbances.

Climate change projections suggest that difficult times may be ahead for the desert tortoise as heat and droughts expand over the region. Like all reptiles, tortoises have minimal ability to self-regulate their internal temperature, and thus must retreat to the shade of vegetation or their burrows once the air temperature reaches above 91 degrees Fahrenheit, in order to keep their body temperatures out of the danger zone. Droughts also force the tortoises to spend more time in their underground burrows to minimize water loss; thus both heat and drought decreasing the amount of time they are able to spend feeding. Droughts limit the availability of nutritious forage for the tortoises.

Females also lay fewer eggs during drought years. Furthermore, the sex of the young turtles is determined by the soil temperature during incubation. Temperatures above 88.7 degrees Fahrenheit produce female tortoises, so prolonged high temperatures could skew the sex distribution of future generations. Extremely high soil temperatures (above 95 degrees) are lethal to the developing young.

Defenders at Work

Defenders was influential in listing the Mojave population in 1989, and in the early 1990s helped secure key acquisition lands. The Mojave population of the desert tortoise is still declining drastically due to staff constraints, funding shortfalls, and lack of public support for necessary recovery actions. The Desert Tortoise was listed under the Endangered Species Act in 1989 and a team of experts developed a recovery plan to guide its recovery in 1994. Currently there is a mandated review of the recovery plan which Defenders is involved in.

Legal Status/Protection

  • Endangered Species Act (ESA): The desert tortoise is listed as threatened.
  • IUCN Red List: Vulnerable. Desert tortoises are listed as vulnerable.
  • CITES: Desert tortoises are listed in Appendix II.
 
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Posted by on May 30, 2011 in Animal in North America

 

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American Crocodile

American Crocodile

American crocodiles (Crocodylus acutus) are well-armored with tough, scaly skin. They are gray-green or olive-green with long, slender snouts, which distinguish them from their cousin, the alligator. Also unlike the alligator, the fourth tooth on the bottom jaw of the American crocodile is visible when its mouth is closed. South Florida is the only place where you can find both crocodiles and alligators.

Fast Facts

Length: 7-15 feet.
Weight: 150-450 lbs.
Lifespan 60-70 years.

Diet

An American crocodile’s diet consists mainly of small fish, invertebrates, reptiles, birds and mammals.

Population

There are more than 1,000 American crocodiles, not including hatchlings, in Florida.

Range

American crocodiles are found in southern Florida, the Caribbean, southern Mexico and along the Central American coast south to Venezuela.

Behavior

American crocodiles inhabit brackish and saltwater habitats and are typically found in coastal mangrove wetlands, ponds, coves, creeks and canals. Decidedly less aggressive than the infamous Nile and Australian crocodiles, American crocodiles are shy, reclusive and rarely seen by people.

Reproduction
Mating Season: January and February.
Gestation: 2-3 month egg incubation.
Clutch size: 35-50 eggs.
In April or May, the female crocodile will build a nest of loose dirt in a mound by the water’s edge and lay her eggs. She buries the eggs and fiercely guards her nest. When the eggs hatch in July or early August, the female helps carry her young to the water. But, unlike the alligator, she will not continue to care for her young.

Climate Change and Other Threats

Once hunted intensively for their hides, today, loss of habitat to human development, illegal killing and roadkill are the greatest threats faced by American crocodiles. As sea level rises due to climate change, a significant portion of crocodiles’ coastal wetland habitat may face saltwater incursion or inundation.

Legal Status/Protection

  • Endangered Species Act (ESA): American crocodiles are listed as endangered under the ESA, except in Florida, where they are listed as threatened. The Florida Endangered and Threatened Species Act lists the Florida population as endangered.
  • IUCN Red List: Vulnerable.
  • CITES: American crocodiles are listed in Appendix I.
 
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Posted by on May 30, 2011 in Animal in North America

 

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