Monday 27 July 2009 Quokka - Marsupial Waste Recycler

While European explorers have variously mistaken them for rats and wild cats, quokkas (Setonix brachyurus) are actually small marsupials, morphologically similar to wallabies and, to a lesser extent, kangaroos but typically smaller. Quokkas can weigh up to 5 kilograms (about 11 lbs); growing to just 54cm (21.3 inches) tall and 30cm (11.8 inches) long.

Quokkas are adapted to the warm climate of Western Australia and the largest population of them is found on Rottnest Island near Perth. Indeed, the island, somewhat indirectly, is named for the presence of quokkas. In 1696, an early explorer of Western Australia (then New Holland), the Dutch sea captain - Willem de Vlamingh, considered the quokkas to be vermin and named the island 'Rottnest', which is Dutch for 'rat nest'. This less than flattering name has, it seems, stood the test of time.

Rottnest Island is something of a safe-haven for quokka, as it is free of fox and cats that were, in fact, only relatively recently introduced to the island by European settlers. Moreover, laws on the island mean that it is illegal for visitors to interfere with the animals in any way. However, the quokkas' complete lack of fear of humans, which means that they remain highly vulnerable to abuse.

There is a small mainland population of quokkas in Two Peoples Bay; however, here the predation threat is a lot higher, particularly from foxes and domestic cats. The animals, therefore, require dense vegetation for cover. On the mainland the quokka are sympatric with Gilbert's Potoroo, another marsupial, sometimes called a rat-kangaroo.

Quokkas are mainly nocturnal and exclusively herbivorous, feeding on grasses and leaves. However, they are thought to be able to survive for extended periods without any food or water. The Rottnest population is thought to have suffered a certain degree of ill health due to being fed inappropriate food-stuffs by tourists, including bread. Visitors to the island are, as outlined above, now requested not to feed or handle these animals.

Quokkas can breed at any point during the year, however, on Rottnest Island their breeding period is usually confined to late summer. Females produce just one joey per year with a gestation period of four months. The joey will reside in the mother's pouch for a further 25 weeks and will continue to be suckled by the mother for an additional ten weeks after that.

Perhaps the most fascinating (and disgusting) facts about the quokka is that they recycle a small amount of their own waste products. Such caecotrophy is common in the animal kingdom and is practiced by many other mammals, including rabbits. It allows for the re-processing of any material that has made its way through the entirety of the animal's digestive system without being fully digested. Such coprophagous behaviour can be expected to be most common during times of low food abundance or extremely high physiological demand (e.g. during pregnancy and/or lactation).

Picture of the Quokka on Rottnest Island WA Australia 2008, by Gavin Williams, licensed under GFDL You can help spreading the word about this animal by liking it on facebook

Permanent Link

Monday 20 July 2009 The Black Wildebeest - A Conservation Success Story

The black wildebeest (Connochaetes gnou) is one of two species of wildebeest; the other is, of course, the more numerous blue wildebeest - well known from natural history documentaries, roaming across the Serengeti. It might surprise you to learn that wildebeest, both the blue and black species, are actually a type of antelope.

The name ‘black' wildebeest is something of a misnomer, as the coat of this species can more accurately be described as ranging from chocolate to very dark brown in color. Its alternative name, the white-tailed gnu, is perhaps better in that it describes the most striking feature of this species; the long white tail. In common with many mammals, the quality of a black wildebeest's coat changes seasonally, becoming thicker in winter; this is clearly a homeostatic adaptation, aiding the maintenance of a stable body temperature.

Black wildebeest are herbivorous. Indeed, their diet is not very varied; consisting almost exclusively of grass. However, black wildebeest are highly sought after components of other animals' diets, with their main predators including: spotted hyenas, leopards, cheetahs, lions and crocodiles. Considering black wildebeests weigh in at anything up to 180 kilograms (that's nearly 400lbs), they are quite a meal for a successful hunter but by no means an easy one.

Facing such a high threat of predation, black wildebeests seek safety in numbers, with females and young males forming herds of between 11 and 50 members. Adult males, in contrast, either live solitary lives or form smaller bachelor groups. Interestingly, females tend to be more aggressive than males, with male mating displays consisting largely of only ritualised combat.

The black wildebeest breeding season starts in February and ends in April each year. They have a gestation period of just over eight months, with mothers generally giving birth to a single calf in either November or December. The young are weaned after four months but will only reach sexual maturity after about two years for females and three years for males. Black wildebeest can live for up to 20 years.

While, the current conservation status of the white-tailed gnu is registered as 'Least Concern', in the recent past their future was much less certain. Indeed, humans, white-settlers in particular, hunted the black wildebeest almost to extinction, and it is thought that all current black wildebeest herds are derived from captive stock rather than natural populations. This is a sad fact in itself, but the currently thriving populations of black wildebeest in north-eastern South Africa serve to highlight the success of captive breeding and release/re-introduction programs.

The reason black wildebeest were so heavily hunted is largely because farmers saw them as pests - the meat was, in many cases, only a by-product of the 'pest' control. Furthermore, the white tails of the black wildebeest were commonly saved for use as fly swats, similar to the way in which the live animal would have used the tail itself. You can help spreading the word about this animal by liking it on facebook

Permanent Link

Wednesday 15 July 2009 Amazon River Dolphin - Pretty in Pink

The Amazon river dolphin (Inia geoffrensis) was first officially described by Henri Marie Ducrotay de Blainville in the early 19th Century and was given the scientific name Inia geoffrensis. However, it is commonly referred to as simply the boto. This species exhibits clear sexual dimorphism with adult males reaching lengths of nearly 2.5 meters (8.2 feet) and weighing up to 185 kilograms (407lb). Females are rarely found to be longer than 2.15 meters (7 feet) and typically weigh around 40 kilograms (88lb) less than their male counterparts.

Another common name for the boto is the pink dolphin. However, pink coloration is generally only present to any significant degree in males of the species, and is the result of scar tissue formation. Competition between males for the possession of females is intense, leading to battles in which both competitors are commonly wounded. Such fierce competition between males may explain why females with young calves tend to avoid the deep freshwater territories of males, preferring the shallower flood plains. In fact, contact between females and males is largely confined to the mating season in late October.

Botos are the largest of the five species of river dolphin and are native to Brazil, Bolivia, Colombia, Ecuador, Peru and Venezuela. In much of its territory the Amazon river dolphin is sympatric with the Tucuxi, however, the two are easily distinguishable. The Tucuxi is similar in appearance to the perhaps more familiar bottle-nosed dolphin. The boto, on the other hand, has an elongated jaw filled with up to 30 specialised teeth for catching and crushing fish. Jaw elongation is thought to have evolved in response to the unique set of selective pressures that accompany a piscivorous diet. Intriguingly, similar adaptations can be seen to have evolved convergently in many fish-eating reptiles, including gharials and the long extinct Ichthyosaurs.

The predatory capabilities of the Amazon dolphin are further improved by its unfused neck vertebrae, which allow the cranium a 180 degree arc of movement. This means that, unlike many other aquatic predators, the boto is not limited to prey directly in front of it. It is thought, due to the murky waters they inhabit, that botos are heavily dependent on echolocation for finding fish. There is also some suggestion that these dolphins can stun potential prey using bursts of sound waves produced by the melon organ, a conspicuous swelling found on their foreheads. It is worth noting that as well as fish, botos eat crustaceans such as crabs, and have even been known to prey upon turtles. This presents the problem of breaking through tough shells; however, Amazon river dolphins have evolved extraordinarily strong jaws for precisely that purpose.

Due to their largely solitary lifestyles and reclusive nature, little more is known about Amazon river dolphins. With their conservation status currently listed as vulnerable, if we are ever to learn more about these fascinating fresh water dolphins, it really will be a race against the clock.

Picture of the Amazon river dolphins by Stefanie Triltsch, licensed under Creative Commons Attribution ShareAlike 2.5 You can help spreading the word about this animal by liking it on facebook

Permanent Link

Saturday 11 July 2009 Four-toed Hedgehog

The Four-toed Hedgehog (Atelerix albiventris) lives in the forests and deserts of Africa. It has a long, pointed snout, round eyes and oval ears. This species of hedgehog gets its name from its back feet. They have just 4 toes each, while its front feet have five toes each (talk about a fascinating anatomy).

The four-toed hedgehog's eyesight is adequate, but they primarily depend on their strong sense of smell and exceptional hearing. Four-toed hedgehogs vocalize by hissing, growling and chirping. These sounds get louder when the animal gets agitated. Their Life span, in captivity, is from 8 to 10 years. Their life span is just 2 to 3 years in the wild, where they are preyed upon by lions and birds. Four-toed hedgehogs eat frogs, snails, eggs, carrion and birds. They also eat peanuts, seeds, roots and even fungi.

The male four-toed hedgehog will court a female by snorting and growling while it moves in circles. After mating, the female will gestate for thirty to forty days. The litter sizes range between 2 and 10 newborns. The newborns are born with their eyes closed. They remain closed for eight to 18 days.

Interesting facts: When threatened a hedgehog will form itself into a ball, hiding its most sensitive body parts, its head, feet and belly. Also, These hedgehogs are very tolerant to snake venom. They are around forty times as immune to venom as the similarly sized guinea pig.

Picture of the four-toed hedgehog by Jkasvi, licensed under GFDL You can help spreading the word about this animal by liking it on facebook

Permanent Link

Wednesday 08 July 2009 White-eared opossum

The White-eared opossum (Didelphis albiventris) is a non-endangered species that lives in much of South America, and can be found in Venezuela, Guyana, Paraguay, Peru, Suriname, Uruguay, Bolivia, Brazil, Ecuador, and Argentina, and more. It is a normally ground dwelling species that can be found in trees, as it goes between them and is an apt climber. The White-eared Opossum is about 1-3 lbs in weight (about a kilogram). The White-eared Opossum is a small marsupial mammal that is covered in black fur, with white guard hairs covering the face and whiskers on the ends of the animal’s narrow snout. Additional white can be found on both sides of its face leading to its ears that are also covered in white fur. Their tails are long and taper off while being covered in dark fur that ends halfway, with the rest of the tail appearing leathery and long.

The White-eared Opossum is a part of the genus Didelphis which has five other species of opossum. Didelphis belongs to the subfamily Didelphinae which has fifteen other genus of opossums, and the subfamily Didelphinae belongs to the family Didelphidae which has one other subfamily of opossum. Finally the family belongs to what is called the “Common Opossums” or Didelphimorphia, an order in the Marsupialia infraclass.

The White-eared Opossum is highly adaptable and can be found in many different climates and among humans. Having been a species, similar to how the coyote adapted in the U.S., to find success alongside humans they are sometimes seen as a pest. The White-eared Opossum is an omnivore and will eat animal matter, plant matter, and insects too. It prefers insects, small mammals and lizards, along with fruits and edible foliage. Because of its adaptability the White-eared Opossum can survive climate changes, such as influx or decrease in the supply of water, temperature irregularities, and various degrees of humidity and overall landscape. Because of its climbing skills it can stay in trees and be arboreal, or if challenged with a different terrain type it can stay on the ground in the brush. The locations they live range from valleys to mountains to fields and urban areas - but the most populous place you will find them is in a semi-deciduous forest with many places to climb and hide.

The White-eared Opossum does have a set breeding period from September to May, with the variant being mostly the rainfall pattern. Like all marsupials, the offspring are born very small and must climb to the mother’s pouch after just a short time in gestation (pregnancy). Within 46 days after climbing into the pouch they will be ready to venture for short times outside of it. The usual litter size is around four to six opossums, however some have had larger, and some have had smaller, as is the case with any animal species. They quickly mature and can mate at nine months of age.

Interesting Facts about the White-eared Opossum:

• The digestion cycle allows for seeds to remain viable after excretion, making the opossum responsible for dispersal of seeds which helps to further the fauna of an area


• The White-eared Opossum has been shown to carry Sarcocystis, a possible but small threat to humans - usually found only in undercooked meat. It is a protist like malaria, so when contracted can be very harmful.


• If it is scared it can play dead, and in so doing will be involuntarily catatonic for up to four hours, and will also excrete a smell from a gland that will normally ward off a predator.

Picture of the white-eared opossum by Abinoam Praxedes Marques Jr., licensed under GFDL You can help spreading the word about this animal by liking it on facebook

Permanent Link

Friday 03 July 2009 Common pipistrelle

The Common Pipistrelle (Pipistrellus pipistrellus) is a species of small bat found over most of Europe, North Africa and southwestern Asia, and especially the British Isles. It is 1.75-2.5inches (33-48mm) long and has a wingspan of up to 8-10 inches (19-25cm), the forearms being 1-1.5 inches (28-35mm long). It generally has dark to chestnut brown fur, with it ventral fur being paler. The ears are short and triangular with a rounded tip, and the wing membranes tend to be opaque. The average weight of the Pipistrelle is 4-8g. It is most commonly found in woods are farmland, but also inhabits towns, often in lofts and buildings and can be seen in the evening sky when the sun just starts to set or has set.

The Common Pipistrelle’s species name is Pipistrellus pipistrellus, and it belongs to the genus Pipistrellus. Within the genus Pipistrellus there are 33 other known living species, making it a very heavily populated genus. Pipistrellus belongs to the family Vespertilionidae (known as evening bats or Vesper Bats). Vespertilionidae is the largest family of bats, and one of the best known. Almost all are universally insect eaters with only a few exceptions that take a liking to fish. The family Vespertilionidae belongs to the suborder Microchiroptera (known as the Microbats) in which all non fruit bat species are a member. Microchiroptera belongs to the order Chiroptera which contains all living and extinct bat species known to date.

Their summer roosts tend to be in the cracks and crevices of old buildings, behind paneling, even in shutters and eaves. The most common building for them to roost is an old barn or abandoned structure since it is quieter and offers peace. During the winter they are most commonly found in trees and buildings, rarely dwelling underground in caves. They emerge around 20 minutes after sunset, earlier on warmer nights and have been know to fly in daylight, although their senses are not as acute for daylight travel and they are vulnerable to predators. Their flight is erratic but agile, generally 15-30 feet (5-10m) off the ground. Males occupy the same territories all year round and fiercely defend them during the mating season, when the species smells strongly of musk and emits unique social mating calls to entice the female bats.

When foraging over water the Common Pipistrelle prefers areas of smooth water with trees on both banks, areas known to be abundant with the flying insects that make up their diet. Individuals will follow the same light routes every night, though the foraging becomes intermittent throughout the night and is very dependent on temperature (greater than 8 degrees Celsius), and their reproductive state. Their prey is consumed during flight and the Pipistrelle has been known to forage up to 5km from its roost in search of insects.

Interesting Facts about the Common Pipistrelle:

• There are en estimated 2 million Common Pipistrelle throughout the British Isles


• The population has declined over recent years, mainly due to farming chemicals in the intensification of agriculture.


• Cats also pose a severe threat to urban populations of Common Pipistrelle.


• The Pipistrelle emits a frequency of between 45-76 kHz, maintaining a medium of 47 kHz with each call lasting maybe 5.6ms.

Picture of the common pipistrelle by Barracuda1983, licensed under GFDL You can help spreading the word about this animal by liking it on facebook

Permanent Link