Friday 30 October 2009 Black Dolphins - one of the smallest species of all of the cetaceans

Black dolphins (Cephalorhynchus eutropia) are known by many other names such as Chilean dolphins, Chilean black dolphins, and white-bellied dolphins. These small cetaceans have blunt, beakless heads and a stock body shape. The average length of this dolphin is 67 inches (1.7 m) and a mature dolphin weighs around 132.27 lbs (60 kg). Their flippers and the large dorsal fin are round in shape. The color of the coat is gray but the ventral sides are light in color. There are white markings on their forehead, throat, lips, and in the area behind their flippers. There is a dark gray band round their throat. There are vertical lines known as fetal folds on a baby black dolphin. It is believed that before birth, the calf is tightly curved in its mother's womb.

Black dolphins are mainly found in cold water. Their habitats are in the shallow coastal waters of Chile, South America, Argentina, Cape Horn, Beagle Channel, and to the south of Isla Navarino. This species is thought to be highly gregarious since they roam about in small groups of 2 to 10 individuals. In the northern range, there are 20 to 50 individuals in a group. Valdivia near Chiloe and the gulf of Arauco are places where these dolphins are found in abundance.

Black dolphins like feeding on crustaceans, fish, and cephalopods. They also eat fish as anchovies, sardines, schooling fish, and squids. Their diet sometimes also includes green algae. There is no information about the reproduction pattern of Black dolphins yet.

Just like other species of dolphins, the black dolphins can also swim very fast. They can cover short distances rapidly with a speed of 20 mph. Then they sense any kind of danger, they swim even faster but at the same time, they get tired soon. At a normal speed, they can swim for hours and can cover long distances with a speed of 4 to 6 mph. Some population of the Black dolphins may migrate seasonally but others remain in one area through out the year.

In southern Chile, dolphins which accidentally get trapped in nets are used as bait to lure crabs or for human consumption. The complex channels and islands make it impossible to protect this species against hunting. The increasing aquaculture industry may have also invaded the habitats of black dolphins.

Picture of the black dolphin by Frank Holden, licensed under Creative Commons Attribution ShareAlike 3.0

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Sunday 25 October 2009 Blue Monkey - A Social Native of Africa

The Blue Monkey (Cercopithecus mitis) also known as the Diademed Monkey is a member of the guenon genus. It is native to East and Central Africa, Ranging from the northern part of the Congo River Basin to the east of the Great Rift Valley and to the south of northern Zambia and Angola.

Although, called 'Blue Monkey', the 'blue' is not really noticeable. The small hair on its face sometimes gives the impression of blue color and hence its name. Apart from its face, its coat is grey or olive in color and there is a yellowish patch on its forehead called the 'Diadem' from which the name Diademed Monkey has been derived. Its legs, feet, and cap are black and the mantle is brown, grey, or olive depending on the species. The Blue Monkey has pouch in its cheeks to carry food while foraging. An average mature blue monkey is 19.68 - 25.59 inches (50 - 65 cm) long and the length of its tail is equal to the length of the rest of its body. The female blue monkey weighs about 8.81 lbs (over 4 kg) and the weight of the male is about 17.63 lbs (8 kg).

The Blue Monkey is mainly found in bamboo forests, evergreen forests, and in thick forest canopies. It very rarely comes to the ground. In order to meet its need of water, it depends on the humid and shady areas where water is found in plenty. Leaves and fruits are its main food but it sometimes eats slow moving invertebrates as well. Tall trees are its most preferred home where it gets both the required shelter and food. Since the green cover is vanishing rapidly, it is also suffering the loss of its natural habitat like other animals. At places where the pine trees are replacing the natural green cover, the blue monkey is considered a threat as it may strip the bark in search of food and moisture. Humans also hunt it for its bushmeat.

The Blue Monkey males are larger than the females. Females generally give birth once in two years during the start of warm, moist rainy seasons. The gestation period lasts for about 5 months. Infants take birth with their eyes open and fur all over their body. The Blue Monkey roosts in groups of 10-40 individuals with only one adult male.

This species believes in the unmale-per-group tendency and the male receives the copulations from the females in the group. The male guards the group from any predators and females also join him in this activity. The stronger male sometimes ousts the male thereby overtaking the troop. In order to protect themselves from predators, these Blue Monkeys get mixed with other species of monkeys. No competition is seen between the two groups since they forage in diverse locations.

This species has a variety of habitats but it always stays close to water. Somalia, Angola, South Africa, Zambia, Zimbabwe, Uganda, Tanzania, Sudan, Malawi, Kenya Burundi, Ethiopia, Zaire, Rwanda, and Mozambique are countries where the Blue Monkey is found in abundance.

Picture of the blue monkey by Pedro Gonnet, licensed under Creative Commons Attribution 2.5 License.

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Friday 23 October 2009 Siberian Chipmunks - Exceptionally Hygienic Omnivores

The Siberian Chipmunk (Tamias sibiricus) is the only member of its genus that lives outside America. Ranging from Russia to China, northern Japan, Korea, and northern Asia, its main habitats include woodlands with thick bushy vegetation.

Its total length from head to tail is 18 to 25 cm (3.93 to 9.84 inches) of which one third is occupied by its tail. The weight of an adult Siberian chipmunk varies according to the season but normally, an adult Siberian chipmunk weighs about 50 to 150 grams (1.76 to 5.29 oz). When compared to its other relatives such as the red squirrel, it is rather smaller in size.

The Siberian chipmunks are omnivorous animals and feed on mushrooms, shrubs, small birds, berries, and small animals. Their diet includes conifer seeds, nuts, and vegetables and they also eat tree buds, wheat, buckwheat, and oats. Chipmunks also prey lizards and insects. Mustelids, cats, and birds are the main predators of the Siberian chipmunk. This species can prove dangerous since it can spread grave diseases like rabies by its bite. Siberian chipmunks have made colonies in some parts of central and Eastern Europe, since they escape easily from captivity.

In some parts of Europe, the Siberian chipmunk is being kept as a pet but it needs a very spacious place for climbing and the place should be covered properly to avoid retreat. They are not much active during winters but generally avoid sleeping for a long time in heated rooms. Their lifespan is short in the wild but in captivity, they can survive for more than 10 years. It is a universal fact that animals born in captivity become disciplined to some extent. The Siberian chipmunk generally enjoys feeding on vegetables, fruits, rodent lab-blocks and nuts.

Like its relatives, it has bright colored fur with dark stripes, and large pouches in its cheeks to collect food. Its ears are small and rounded up at the ends. The color of its fur depends on the origin of the animal. The fur is brown grey or tawny yellow. Along its flanks there are five dark and four light colored long stripes. The color of its tail is light brown and there are thick black lines on both sides with small white edges.

They mainly live in forests. Their needle-pointed claws make them a superb climber but most of the time, they stays on the ground. They construct lodges on the ground to live in and in order to store food, the Siberian chipmunks bury their food 5 to 7 cm under the ground. They are hygienic and clean themselves from head to tail. Sometimes, they even clean one another. They make various sounds including a bird-like 'cheep' short whistle which lasts only for 1 or 2 seconds. They make this sound 5 to 6 times constantly when they smell any danger. They are most active during the day time.

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Monday 19 October 2009 Nubian Ibex - The Resolute Combatant

Previously, the Nubian Ibex (Capra nubiana) was known as Capra Ibex nubiana. One can easily recognize Nubian Ibex by its majestic backward-arching horns which are slender, long, and curve toward the outer side at the edge. Its beautiful horns cast a glorious silhouette against the striking rocky mountainous land of its habitat. Although both males and females have horns, males have much larger horns which grow up to 120 cm (48 inches) against 35 cm (14 inches) of females. Coat of the Nubian IbexCapra is light sandy brown in color. Its underbelly is white and its legs are marked with black and white dots. There is a dark strip running downwards on the back of the males and with age, they grow dark and develop a long beard. When the October rut starts, the color of the chest, neck, shoulders, upper legs, and sides turns dark brown which almost looks like black.

The Nubian Ibex is mainly found in Northern Parts of Africa and some parts of Arabia, Ethiopia, Egypt, Jordan, Israel, Saudi Arabia, Yemen, and Oman. Previously, it was also found in Syrian Arab Republic and Lebanon. This species dwells in the rocky deserts on the mountains where the weather is rough and dry at higher elevations which may rise up to 22,000 ft. During summers, the Nubian Ibex moves to mountainous regions to stay away from heat and in winters, it returns to the lower altitudes.

There can be 20 to 25 animals in one herd all of a single sex and their young ones roam with their maternal family till they are three years old. The mating in case of Nubian Ibex occurs in late summer, especially in October. The strongest male competes and fights with other males to get breeding rights by pushing other males with its horns. Gestation period lasts for around five months and in March, the young ones take birth. Normally, there is only one young one at a time but sometimes, the female may give birth to twins or even triplets; this, however is a very rare case. At the age of three, they reach their sexual maturity and this is the time to leave the herd. Average lifecycle of a Nubian Ibex can be up to 17 years.

This species has a tendency to remain most active during the daytime and rest at night. It is believed that its light colored, shiny coat reflects the solar radiation due to which it is able to remain active even during the hot summer days. It is a very alert animal and during daytime, it often maneuvers down steep and precipitous regions to graze leaves and grasses and later, returns to the rocky areas at night. It usually faces danger from such predators as eagles, bearded vultures, and leopards. When threatened, it rises on its strong hind legs and faces the threat by pointing its powerful-looking horns at the predator.

Picture of the Nubian Ibex by Stavenn, licensed under GFDL.

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Saturday 17 October 2009 The Health-Conscious Jamaican Fruit-eating Bats

The Jamaican fruit-eating bat (Artibeus jamaicensis) is also known as the Mexican or Common fruit-eating bat. The Jamaican fruit-eating bat is found in South and Central America. Although not very common, it is found in the Southern Bahamas as well. Its most distinctive feature is that its external tail is missing and it has a U-shaped and a very minimal interfemoral membrane. It has a grayish brown coat and its underside is slightly pale. It leaves mild and soap-like odor and has a nose that looks like its third ear. Unlike other bats, its ears are pointed at the ends. The Jamaican fruit-eating bat is 9 cm (3.5 inches) in length.

It mainly dwells in deciduous scrub or rainforests. With the help of the leaves of Palmae and Araceae plants, it builds a type of tent. It is also found in caves, forest foliage, and hollow trees.

The Jamaican fruit-eating bat belongs to the set of nocturnal animals. As its name suggests, it likes eating fruits. It mainly feeds on cecropias, figs, papayas, bananas, and guavas. Sometimes, when fruits are not available, it also feeds on pollen, nectar, leaves and even insects as well. Sometimes, it has to fly for 10 to 15 miles at a stretch in search of fruit trees. After finding a fruit, it carries the fruit in its mouth and flies off to a dining perch to eat it. It bites into the fruit and to break it and get the juice, it presses it in the mouth. The rough roof of its mouth helps it to squeeze out the juice. After squeezing the juice, it breaks the fruit to eats its flesh. Fruits with big seeds are left, since it generally swallows small seeds.

One important fact about the Jamaican fruit-eating bat is that among mammals, it is considered quite efficient in food digestion. It takes this bat just fifteen minutes to process the food. This is the main reason that the small seeds which had been swallowed earlier are left undigested. The seeds are re-released which helps in the dispersing of seeds.

A thorough research is being carried out on the ecology of different bat species on Barro Colorado Island, a natural reserve run by Smithsonian Tropical Research Institute in Panama. Under the supervision of the scientist Elisabeth Kalko, over 10,000 individuals of the bat species were examined, measured and marked for the BCi project on bats being carried out under the supervision of Elisabeth Kalko.

The female of Jamaican fruit bat is known to bear only one young at a time. At higher elevations, the birth takes place only once a year while in Panama, it happens twice a year. Bearing two young ones at a time is very uncommon. February to July is usually the breeding period of the Jamaican fruit-eating bat. Usually, when it is its mating season, the birth of young ones is very rare and there is a very short period in a year when the birth is at its peak. Life expectancy of this species is very short, only two to three years on average.

Picture of the Jamaican Fruit-eating bat by Tobusaru, licensed under Creative Commons Attribution 3.0 Unported.

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Sunday 11 October 2009 Muskrats - Water-loving Rats

The Muskrat (Ondatra zibethicus), is a semi-aquatic, medium-sized rodent. It is found in North America and has also been recently introduced in Asia, South America, and Europe. The main habitat of muskrat is wetlands but this animal can successfully adapt to different habitats and climates. It is very beneficial to nature and important to humans for its fur and as food.

Muskrats are not the true rats which belong to the genus Rattus. There are two scent glands near its tail which give off a strong musky smell that is used by muskrat to declare its territory. It is this attribute of the muskrat that has given it its name.

The size of an average muskrat is around 16 - 24 inches (40 - 60 cm). The size of its tail is almost double its body size and it weighs about 1.5 - 4 lb (0.7 - 1.8 kg). An adult muskrat is just a little longer than the brown rat but it weighs four times the weight of brown rat. It has a medium or dark brown coat with small but thick hair and the color of its belly is lighter than the body. The two-layer fur protects it from cold water. Instead of hair, they have scales on their long tail which flattens vertically to help them in swimming.

Muskrats spend a lot of time in water. They can stay under water for more than 15 minutes. They have the ability to close their ears when under water. Their semi-webbed hind feet help them a great deal in swimming but their tail plays a main role as a means of propulsion.

They are found in marshy lands close to salt water or fresh water wetlands, ponds, rivers, or lakes. Since the construction of canals and other irrigation channels is being created on large scales, muskrats are especially becoming common in these areas. Muskrats can survive in areas where sulfurous water from coal mines is released. Muskrats may occupy that area of water where other animals such as frogs or fish perish.

Like other rodents, muskrats are also prolific breeders. Females can give birth to 2-3 litters per year and there can be 6-8 young ones in each litter. The babies are very small and weigh only 0.8 oz (22 gm) at birth. In warm environment, it matures just in six months while in a cold climate it may take one year to mature.

Muskrats are active when it is cool at night, dawn, or dusk. Aquatic vegetation or cattails are their main food. Although plant materials fulfill 95% of their food needs, sometimes, they may also eat small animals such as frogs, fish, and mussels etc.

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Tuesday 06 October 2009 Deer Mouse - The Foliage Lover

The deer mouse (Peromyscus maniculatus), is found in North America. This species can also be the cause of dangerous diseases as lyme and hantaviruses. It comes in the same genus, Peromyscus, as Peromyscus leucopus, the white-footed mouse.

Physical Description:

If the tail of the deer mouse is not considered, then the animal is hardly 7.5 - 11 cm (3-4 inches) long. Its weight is around 15-32 g (0.52-1.12 oz). They have good eyesight and hearing power because of their large eyes and ears. The soft fur of the mouse may vary in color from black to white but all the deer mice are white from underside and have white feet.

Behavior:

Deer mice are known to be nocturnal creatures that generally spend time playing in areas where there are trees. They also like inhabiting a place where there are burrows having nests made from plant materials. The litters of the deer mice are taken care of by the female mother in an individual home. The mouse does not like its litters to get mixed in the group. When the litters grow, the mouse interacts only with its own kind of litter but not with other litters. The homes of the deer mice, although individual, generally overlap. When such overlapping occurs, the probability of mixing of opposite sexes is more than mixing with the same sex. Deer mice which form a part of the overlapping process during the development stage tend to interact with each other more often.

Life Span and Reproduction:

When a detailed study was conducted, it was found that less than 50% of the total population of male and female deer mice left home to reproduce. This led to a conclusion that they usually mate within the same family and so the overall flow of genes is limited among this species. Reproduction can be done by female mice throughout the year. This is the main reason why deer mice reproduce intensely and rank among the most frequently reproducing animals in their species, even more than the reproduction frequency of mammals. The female mice grant permission to the male mice to keep the litter together and keep them warm, which is very essential for their survival. Although their life expectancy is lesser than 96 months, the average life expectancy of the deer mouse is 45.5 months among the females and it is 47.5 as far as the males are concerned.

Habitat:

The deer mice are generally found in regions like Canada, Alaska, and in some parts of South America. Most of these generally live in hollows that are created at a higher height in a tree. It is common among deer mice to house alone but they may stay along with the mouse of the opposite sex. They have a huge population in the wooden areas or in the mountainous areas. The deer mice are considered to be nocturnal creatures.

Diet:

The deer mice generally like seeds, arthropods, leaves, fruits, fungi etc. Their food habit is not the same throughout the year, since the diet keeps changing according to the season and availability of the type of food. During winters, arthropods form 20% of their diet. These arthropods generally include heteropterans, caterpillars, and spiders. Seeds become the main part of their diet during the spring season as their availability increases along with other types of insects. Deer mice also consume tree leaves in a good quantity during spring. They like thriving on fruits and seeds during the summer season. The deer mice will gradually change their food habit in the fall season as per their usual winter diet.

p.s. The deer mouse is not to be confused with the "mouse deer".

Picture of the deer mouse by 6th Happiness, licensed under Creative Commons Attribution ShareAlike 3.0

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