Sunday, 28 November 2010

Miscellaneous Mammals 3: The Long-Nosed Potoroo

Long-Nosed Potoroo
 Sharing the enclosure of the Sugar Gliders I discussed last week is our pair of Long-Nosed Potoroos, Potorous tridactylus. These are strange and specialised relatives of the kangaroos and wallabies and along with a few related species are placed in the family Potoridae. The group is sometimes referred to as rat-kangaroos, but these days they are usually referred to as Potoroos or Bettongs. They seem to be a very ancient group, and seem to have retained the ancient lifestyle of the common ancestor they share with the more open-country adapted wallabies and true kangaroos.

Monday, 22 November 2010

Miscellaneous mammals 2: The Sugar Glider

In Twilight World, our nocturnal house, one of the more easily overlooked species are our Sugar Gliders, Petaurus breviceps, of which we currently have 6. This is about the only commonly seen gliding mammal to be found in the world’s zoos, and is also widely known in the pet trade, but there are a few other species in its genus and some more distantly related forms may be found in some collections. Currently there are 6 species in Petaurus, but this may change (see below),

The feature of Sugar Gliders that give them their name is the patagium, a flap of skin between the front and hind legs which stretches out to form a gliding membrane when the animal jumps from a tree, either to travel between trees or to escape from a predator. If the wind is right, a sugar glider can travel as much as 100m in a single glide, although 10m or so is more usual. Sugar gliders are small mammals, about 40cm long, of which more than half is tail. The weight is 100g – 150g, with males weighing more.

Saturday, 13 November 2010

Miscellaneous Mammals: The Sand Cat

When you enter Twilight World, the nocturnal house at Bristol Zoo, one of the first animals you will see are our three Arabian Sand Cats, Felis margarita harrisoni. Sand Cats (there are six subspecies described) have a vast range, extending from Algeria in the west to Baluchistan in central Asia, and have recently been reported from Syria.

Although in many ways similar to the domestic cat (which derives from the Africa Wild Cat Felis sylvestris lybica), Sand Cats have many specialisations for their desert lifestyle and need specialised accommodation in captivity. Most are shown in nocturnal houses, although this is not strictly necessary as they will be active in daylight if food is involved. Incidentally, Bristol pioneered the reverse lighting scheme that enables visitors to observe nocturnal animals during their activity period. The current version opened about 13 years ago.

Sunday, 7 November 2010

Trees of Bristol: The Ginkgo

 At this time of year, among the fallen leaves can be seen the distinctive fan-shaped leaves of the zoo’s Ginkgo trees. Ginkgos can be seen in many parts of the world today, as they make good street trees. Ginkgos adapt well to the urban environment, tolerating pollution and confined soil spaces. They rarely suffer disease problems, even in urban conditions, and are attacked by few insects. That they are to be seen anywhere however is a major triumph of survival, as Ginkgos are among the oldest living plants.

'Autumn Gold'
For centuries it was thought to be extinct in the wild, but is now known to grow in at least two small areas in Zhejiang province in Eastern China, in the Tian Mu Shan Reserve. These populations may have received at least some assistance by local people in their survival, as ginkgos are often grown in the grounds of Buddhist monasteries.

Prior to their discovery by western explorers of China, Ginkgos were only known to western science as fossils, mostly of leaves. The fossil record of the group reaches back to the Permian period, 270 million years ago, and at their height there were at least 16 genera with a variety of forms. Some were like the trees of today, others were more shrubby and with divided leaves that must have made them look rather like Japanese maples. Their origins are unclear (this is the case with most plant groups), as in some respects they resemble cycads, in others conifers. The mostly likely origin is a group generally referred to as the seed ferns, as they had fern like leaf structures but produced seeds like more advances plants..