A CROAK FROM BEYOND THE GRAVE

Preserved specimens at museums always draw a crowd due to the extraordinary rarity to see whole animals preserved in liquid. Not only are they are crowd pleasers; they allow museums to catalog species we know exist on this planet.  An exciting new discovery by graduate student Tina Cheng and her team will put museum specimens to another great use.

The main focus of this study was the fungus Batrachochytrium dendrobatidis (Bd) and it’s spread across Mexico and Central America. Bd causes chytridiomycosis, a disease that is currently devastating amphibian populations with approximately 40% of total species affected by it. The disease changes both morphology and behavior and eventually leads to death.

Museum specimens are normally preserved in formaldehyde, which interacts with proteins found in DNA. This allows the fixation of body tissues to occur. Ms. Cheng and her team were able to use old specimens from the Museum of Vertebrate Zoology in Berkeley, Calif, to establish where and when the deadly fungus Bd first appeared.

Swabs were taken from frog and salamander specimens (collected in the 1960s) that inhabited the mountains of southern Mexico, western Guatemala and the cloud forests of Monteverde, Costa Rica. Interestingly, the swabs showed the presence of Bd corresponding with the earliest reports of Bd related deaths of amphibians in the wild.

Ms. Cheng and her team were effectively able to take a ‘freeze frame’ of time to show the spread if the disease. It appears Bd spread in a southerly direction across Central America in the 1970s – 1980s.

Using museum specimens in molecular research is a massive step forward in research science, as it was previously believed formaldehyde would denature the proteins needed for testing in DNA. Encouragingly, this study shows tiny stretches of DNA can survive the preserving process, leaving the opportunity for additional research to be conducted using museum specimens. As scientists are currently in the process of establishing how Bd spreads, how to stop it and how to treat infected individuals, this new research method could not have come at a more important time.

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THE NOT SO GLAMOROUS WORLD OF EXOTIC PETS

The ownership of exotic pets has been brought to the forefront of people’s minds recently with instances of ownership being reported in the media. Having pets such as lions, tigers and chimpanzees, is not only harmful to the animals but also to the owners. Inappropriate, emotional bonds are formed between humans and domesticated ‘wild’ animals that will never lose their natural instincts.

One notable occurrence has been that of the Vietnamese vet Terry Thompson, who released 56 of his exotic animals into Ohio farmland and took his own life after doing so. The menagerie of animals included: 18 rare Bengal tigers, wolves, bears and monkeys, which had to be shot before they came into contact with the general public. The whole incident is speculated to have occurred due to financial difficulties of keeping so many exotic pets.

Louis Theroux has also just released a new documentary about the ownership of exotic pets in order to gain an insight as to why people believe they should own such powerful and dangerous animals. The programme was filmed once again, in Ohio where the number of exotic pets is high as the state laws are relaxed in relation to the worlds view on owning exotic pets. The limited control of exotic animal ownership is not without consequences, as 75 people have been killed and over 1500 injured by their pets.

Both these news stories highlight how dangerous these animals can be, but why do people continue to buy them? It may be that the dangerous animals are used as power symbols to enhance their owners status, for profit by selling body parts, or because cubs and primates have the cute factor when young. But when these cute animals grow up, they often outgrow their enclosure, become expensive to keep and aggressive as they reach sexual maturity. It is for these negative reasons that out of control pets are given away to establishments such as those featured in Louis Theroux’s documentary. This gives a justifiable reason for keeping them open, in addition to using them as gene pool in the future.

However, despite their proposed usefulness in the future, can conservation organisations really rely on these establishments to make sure the gene pool of endangered species are not compromised by inbreeding when it is normally controlled by an overseeing body? With approximately 5000 Bengal tigers (5% in recognised zoos) kept in captivity in 2004 in the USA alone and only 3200 Bengal tigers in the wild, this is an increasingly important question to consider.

Keeping exotic animals is not a practice everybody agrees with and less than 24 hours after the massacre in Ohio was reported to the general public, approximately 28 000 people signed a petition to ban the sale and ownership of wild animals. There needs to be a shakeup in terms of the laws surrounding owning a dangerous animal as a pet. It should not, in today’s society, be acceptable to be able to buy unchecked numbers of tiger cubs in car parks for $200/cub as reports suggest. Nor is it acceptable for the owner to put themselves in constant risk of being attacked and killed by a loved pet.

If laws surrounding wild animal ownership are stringently controlled in countries which currently permit it, they could provide an invaluable service to conservation in the future. This is because the release of endangered, captive bred individuals into the wild may be considered as a way to reverse depleted populations. But until it is controlled, how long before we hear of another incident similar to the one in Ohio or before an owner is killed?

KILLER WHALE CHANGES ITS COLOUR

Whilst watching Frozen Planet, has it crossed your mind why the killer whales in the Antarctic are slightly off colour? This slight yellow tinge is caused by nutrient rich diatoms and algae found in these chilly waters which attach to the mammals skin. John Durban of the NOAA has offered a new proposal as to why a certain type of killer whale will migrate thousands of miles in relation to this yellow tinge.

Since the killer whales travel at a constant speed during this migration, researchers believe that they are not traveling to find prey or to give birth. Type B killer whales (which feed mainly on seals) were tagged off the Antarctic Peninsula and it was revealed that they move towards sub – tropical waters continually. One tagged individual travelled over an incredible 5, 000 miles to Brazil, only to return just 42 days later to Antarctica! The speed and distance travelled is unprecedented in killer whales and it implies the individual departed from Brazil immediately, but why?

Killer whales return from this journey to warmer seas ‘cleaner’ than when they left. It is thought the warmer water helps killer whales to shed the algal growth and regenerate skin tissue. It is possible that the energy they would need to expend in the cold Antarctic waters can be utilised to repair any tissue damage created by diatoms or algae. Further evidence for this theory is shown by killer whales actually slowing down their speed in warmer waters. They do not travel slowly enough to indicate calving or extensive feeding, but it would give the killer whales extra time in warmer waters to shed and heal their skin.

As more research is conducted on these beautiful mammals, the more we are finding out about how clever they are. This may provide interesting comparisons when researching into the evolution of intelligence and how similar to the intellectual capability of humans they may be.

A unicorn whale?

You would probably recognise them by their distinctive appearance, but how much do you know about the toothed whale, the narwhal? It turns out researchers are also vague about the specifics of a narwhal’s life and how it may change as a result of global warming.

The WWF are trying to establish how Arctic melting is affecting ice – associated species such as the narwhal. Dr. Peter Ewins of WWF-Canada and his team tagged nine individuals in August of this year to try and establish how the elusive narwhal would cope with shrinking sea ice. Dr. Ewins is waiting on the results of their movement patterns to compare with anecdotal evidence of local Inuit’s to try and initiate a successful conservation plan. This is because narwhals are classed as near threatened by the IUCN, with their population at only approximately 50,000 – 80,000 individuals due to hunting practices for their meat and tusk.

Their long, helical tusk was thought to have initiated the fairytales of unicorns and who could blame anyone for being inspired by this mysterious species! The tusks originate from their left canine tooth and males can have tusks that reach up to 3m in length and in 1 out of 500 males, two are produced! Females also possess a tusk, but it is shorter and is not helical in shape. It is thought the tusk has evolved via sexual selection in a similar process to that of the peacock and its feathers. In addition to this, you may have thought the tusk could be used to break through ice patches enabling the narwhal to migrate with ease. However, it is thought the tusk is only used as a visual display to others as they are very rarely observed using their tusk in aggressive behavior.

They are the preyed upon by polar bears, orca and of course, humans, which further depletes their population. In addition to this, narwhals have a highly specialized diet (and therefore restricted) possibly hampering the recovery of their population in the future. When the results from this study are published it will provide greater knowledge to the scientific community when the time comes for a conservation plan for this unique species.

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