Lizards 7: Utila Iguana

Currently the second largest species of lizard in the Bristol Zoo collection, the Utila iguana Ctenosaura bakeri is also one of the most threatened, as it is currently classed by the IUCN as Critically Endangered. Part of the reason for this is its microscopically small range – it is confined to around 8 sq.km of mangrove swamp on Utila island, off the north coast of Honduras. There are currently 15 recognised species of Ctenosaura, with a natural distribution ranging from Baja California and Mexico south to Colombia, although 2 species have been introduced to Texas and Florida.

Book Review: Tuatara: Biology and conservation of a venerable survivor by Alison Cree

There are very few species of small(ish) reptile which are famous outside their native range unless they are venomous or brightly coloured, but the Tuatara Sphenodon punctatus of New Zealand is certainly among that select number. Their fame is due to their being the sole survivor of a unique lineage of reptiles separate from the turtles, the archosaurs, and the lizards, although they are most nearly related to the last, although since they split from the common ancestor with the lizards well over a quarter of a billion years ago even that is not close. The book reviewed here is a summary and survey of the whole of tuatara-related research, and covers not just the biology and ecology of the living animal, but its evolutionary history, interactions with humans, and their past, present, and future conservation status.

Book Review: Extinct Madagascar: Picturing the Island's Past

Details: Extinct Madagascar: Picturing the Islands Past by Steven M.Goodman and William L.Jungers, plates by Velizar Simeonovski. Available from Amazon.

Red Bellied Lemur

I thought I would add an occasional post for book reviews that might be of interest to readers, so I am starting with this one. It is an overview of the recently extinct fauna of Madagascar, of which there is sadly far too much, as anyone who is interested in the current ecological disaster on the island will be well aware. Part 1 covers the geological history, colonisation history (both animals and humans), and the vegetational types on the island. Part 2 is structured around a series of colour plates of sites where subfossil remains of the fauna have been located, accompanied by descriptions of the animals illustrated and what the various sites mean for the complex history of the island over the 2000 or so years since human beings colonised the island.

Lemurs 2: The Mouse Lemurs

Grey Mouse Lemur

Perhaps least changed from the stock ancestral to all other lemurs, the mouse lemurs or Cheirogaleids are a diverse group of small to extremely small, nocturnal primates. They include the smallest of all lemurs, the Pygmy Mouse Lemur Microcebus myoxinus, and here at Bristol we have a succeful family group of the almost equally minute Grey Mouse Lemur, Microcebus murinus.

Lemurs at Bristol, Part 1: What is a lemur anyway?

Ring-Tailed Lemur

One of the most important groups of primates to be seen at Bristol or any other zoo is the lemurs of Madagascar. Confined only to that island (with human introduction of one species to the Comores) they represent a unique radiation of primates in isolation from other primate species, a process which has been going on for many millions of years, possible even before the extinction of the dinosaurs. After thriving on the islands for all that time, around 2000 years ago they encountered disaster in the form of human colonists (not from nearby Africa, but from clear across the Indian ocean in Indonesia). Since that time, many species have become extinct, and the rest are all highly threatened.

Review of the year part 2: In-situ projects

As well as the various education and captive breeding programs run from Bristol, the zoo is also involved in several in-country projects all over the world, usually as part of a consortium with other zoos and conservation organisations. Here are some of the projects we are involved in, and links to where you can find out more.


Cameroon

orphaned chimps at AAA

The bushmeat trade in Africa is one of the major threats to Africa’s wildlife. Contrary to what is commonly believed, this is not a subsistence-level practise, rather in many cases a supply of expensive wild meat to the cities for high-end purchasers. As a result of the hunting of primates especially, a large number of orphans result. These tend to be kept for a while and then eaten later, but with improved law enforcement many are now confiscated and go to various rescue centres. Since 1997 Bristol has been working with the charity Ape Action Africa, providing veterinary support, education training, and publicity for support and care, with possible eventual rehabilitation, at the Mefou National Park. There are already a small number of regular visitors, and the potential for increasing eco-tourism is certainly there.

Review of the year part 1 - Bristol 2012

We are nearly at the end of 2012 so we will finish off the year with some of the new highlights from the last twelve months, starting with Bristol Zoo in this post and finishing off with some round the world news next week

January

Newborn stingray

Babies have been born to two new stingrays which arrived at Bristol Zoo last summer.

Nine ocellated freshwater stingray pups were born last week after two new females were introduced to the Zoo’s male stingray last year.

The new females, sisters named Catalina & Genevieve, arrived at Bristol Zoo from

Weston Seaquarium and have wasted little time in breeding. Catalina has produced six pups and three pups are from Genevieve.

June Research Colloquium - Conservation and Development – some perspectives

This month’s colloquium was a talk by Neil Maddison, who is in charge of our conservation programme links here at Bristol, with some insights into the problems faced by conservation programmes. The focus was primarily on our work in partnership with Durrell Wildlife Conservation Trust, which we are involved with as part of the conservation project for the Livingstone’s Fruit Bat Pteropus livingstonii. (image taken at Bristol)


All too often it seems to me, conservationists focus entirely on the species they care about, without any regard for the people, especially the locals, who are at the centre of the problem. The Comoros is a good example of work Bristol is helping to pioneer in aiming for a more broadly based approach.

April Research colloquium: Rhinos of the Caribbean

This month’s talk was given by John Bendon, an artist working with the Iguana Specialist Group of the IUCN, and was an overview of the magnificent Cyclura ground iguanas of the Caribbean. We have an adult pair at Bristol of one of the largest species, the Rhinoceros Iguana of Haiti and the Dominican Republic, which has a length nose to tail of over 1m and has adult males that can weigh 10kg. Last year, we bred them for the first time, producing 17 young of which 5 can be seen on-show and the remainder are being held off-show for growth studies.


There are currently at least 17 distinct species and subspecies of ground iguanas recognized, but in reality every small cay (flat coral island) or larger island harbours a local form that can often be identified, at least by DNA work. This is still only a fraction of the diversity that may have formerly existed – as with giant tortoises, human predation combined with introduced pigs, cats, dogs, and mongooses has called local extinctions, especially on small islands. At least one species, the Jamaican Iguana Cyclura collei, was believed extinct until rediscovered in the 1990’s, and despite extensive conservation work still only has a population of perhaps 100 adults in the wild, with few young surviving.

February Research Colloquium - Partula, past, present, and future

Some decades ago, at the start of the introduction of biochemistry to the study of animal diversity, a research project was undertaken on the endemic live-bearing snails of French Polynesia belonging to the family Partulidae, especially to the widespread genus Partula. The studies were aimed at disentangling the primary engines of evolution of diversity, in other words was the multiplicity of species due to natural selection, random events, genetic drift or something else entirely? Unfortunately, while the debate was raging disaster struck the study populations.


The Giant African Snail (seen in many pet shops in the UK) was introduced by a misguided local entrepreneur as a potential food source. Finding that no one wanted to eat his livestock, he let them go, with disastrous results for the local peoples crops. That was only the prelude however. The real disaster was a misguided attempt at biological control, which took the form of the introduction of the Rosy Wolf Snail Euglandina rosea. Euglandina originates from Florida, where it is a generalist predator of snails and slugs (it is also sometimes cannibalistic). However, it has a preferred size of prey, and Giant snails are simply too big for it once adult. What was the right size however, was the different species of Partula. As with many island species, Partula has a low reproductive rate, only managing a potential 7 fold increase in a year, compared to Euglandinas’ 57 and the Giant snails 500. The result was a mass extinction event, and it was believed that all the Partula in the wild were either extinct in the wild or headed that way.

January Research Colloquium: Thai Bats, past, present, and future

This year’s series of monthly research presentations started with a very interesting report by Alice Hughes, who is a PhD student at the University of Bristol and one of our volunteers.
Bats as a group are hard to study, as they are hard to locate or observe, and are consequently much neglected even in areas where there is a lot of interest. The UK for example has a well-developed network of bat study groups – I went on a bat walk led by one towards the end of last year where we used bat detectors to track Common Pipistrelles and Noctules in the middle of Bristol. The only tropical bats that have been studied in much detail are the various fruit bats, and they are not typical of the majority of species, being mostly large, vegetarian, and roosting in many species in large colonies in the open.

The current list of species known from Thailand is 121, and many more probably remain to be identified (many bat species can only be told apart by their ultrasonic calls without DNA analysis). Each of these species has its own preferred set of environmental conditions, which explains their often restricted ranges. Alice has been studying the bats of Thailand in order to obtain a predictive envelope of the various conditions required, to enable the extrapolation of how species will fare in the future, and have fared in the past, under different climate conditions. Probably the most well known is the Bumblebee Bat, Craseonycteris thonglongyai. Interestingly, the Thai population appears to have slightly different requirements to the one in nearby Myanmar, which is also genetically distinct, although whether this means there are actually two species or simply local subspecies is unclear.

October Research Colloqium - the importance of lighting

Wednesdays colloquium was a very interesting presentation from Rowena Killick BVM&S MSc (Wild Animal Health) MRCVS, who is the RCVS Trust senior clinical training scholar in zoo and exotic medicine and surgery here at Bristol Zoo Gardens, on a research project she carried out on the Vitamin D levels of some of the new world primates and lemurs here at Bristol.

Vitamin D is synthesised in the skin when it is exposed to UV light of the correct wavelengths from precursors in the diet, and then circulates in the blood to the kidneys where it is converted into the hormone 1,25-dihydroxyvitamin D3, which is a hormone that is involved in the regulation of calcium metabolism. There is a chemically related form called Vitamin D2, which does not have such a potent effect.

The primates of Central and South America (platyrrhines) have an odd biochemical quirk compared to those of the Old World. Their internal organs are resistant to the effects of Vitamin D3, and they cannot use Vitamin D2 at all. In order to maintain proper calcium metabolism, they have circulating blood levels of D3 which are ten to one hundred times higher than similar monkeys in Africa or Asia. Living as they do close to the equator, producing sufficient active D3 is of course no problem in their home range.

The potential problem we have is that Bristol is at mid latitudes in the northern hemisphere, whereas the two groups of primates mentioned earlier all live close to the equator. In humans, lack of exposure to sufficient ultraviolet light causes serious health problems such as rickets, and even sub-clinical levels of vitamin D deficiency can result in problems with fertility, disease resistance, or even potentially cancer. Our primates all have access to outside enclosures year round, so the question is, is this sufficient?

This past year as part of routine health checks the blood vitamin D3 levels of lemurs and new world primates were measured. Although levels of Vitamin D3 were within normal ranges for published data (in fact the lemurs were at the high end), the NWP’s were at the low end, especially in winter, and there was some indication of lower bone density than would be ideal.

So, what does this mean for the husbandry of New World Primates? At present, most zoo primates are given a primate pellet which has supplementary D3 added, as well as a variety of fruit and vegetables. At Jersey metabolic bone disease in Pied Tamarins was cured by providing UVB lighting, and indications are that this kind of lighting should become standard for New World Primates without access to tropical, or at least sub-tropical, sunlight in outdoor enclosures. This would be better than providing additional dietary supplements, as the risk of overdosing would be much lower – like most vitamins, excess Vitamin D is potentially seriously toxic.

The other requirement is of course more research. The various primates of the Americas are enormously diverse, and may have requirements for more or less D3 depending on the species. For example, the nocturnal Owl Monkeys or Dourocoulis, Aotus, have apparently no higher D3 levels than Old World primates. On the other hand, some South American species like the Uakaris are notoriously difficult to breed in zoos – could a higher Vitamin D/UVB requirement be the cause?

(Image from Wikipedia)