Secret and amazing life of dead animals
HAVE YOU EVER watched ‘Night at the Museum’? Remember when Ben Stiller’s character, Larry Daley, is doing his night rounds, comes across a T-Rex skeleton having a drink at the water dispenser and then has to run for his life as it starts to chase him down the corridors?
‘Night at the Museum’ gave life (literally) to a dead exhibit that finds its place in every museum around the world.
For Dr Peter Wimberger, however, “Creativity is the limit to the use of Natural History Museum.”
Dr Wimberger currently is the director of the Slater Museum of Natural History and a professor at the University of Puget Sound in Tacoma, Washington.
In his talk called ‘Secret and Amazing Life of Dead Animals’ organised by Friends of Sarawak Museum (FoSM), he spoke about how dead specimens were more than just stuffed animals sitting pretty in a glass case; they were the source of research, education and inspiration.
Specimens can include skins, skeletons, plants and the whole animals. Only over the last 20 to 30 years, have people started to collect tissue samples as well.
Locality data and dates are essential in collecting the specimens. Other data such as species, name of the collector, sex, stomach content and so on are also jotted down.
In the olden days especially during the Renaissance era, animals and plants were collected for private collections which they called ‘cabinets of curiosities’.
Fast forward to present-day museum curating, and Dr Wimberger says there were four functions for animal specimens that collectors in the past never thought of nor had the technology to execute:
1. To extract DNA for genetic study
Thanks to movies such as Jurassic Park and the Lost World, most of us have a general picture about DNA-extraction and cloning.
A real-life (and maybe less epic) case where researchers extracted DNA for animal propagation was the Greater Prairie Chicken.
Currently ranked as ‘Vulnerable’ on the conservation status scale, Dr Wimberger explained that the breeding success of this species in its native range in Illinois, USA was previously less than 10 per cent.
“One thought was maybe they were facing inbreeding depression, as the population is so small essentially they were breeding with relatives. One question researchers asked was whether there was more genetic diversity back then compared to now, ” said Dr Wimberger.
To answer this question, they extracted the DNA of hundred-year-old Greater Prairie Chicken specimens in the museum to see if the population of this chicken in the past was more genetically diverse than now.
The results did confirm their suspicions, revealing that 100 year old population of this native North American bird was more genetically diverse than the current population in Illinois.
So Greater Prairie Chickens from other states such as Kansas and Nebraska were brought into Illinois to encourage the grouse to breed.
Within two years, the hatching success was increased from less than 10 per cent to more than 60 per cent.
2. To detect pathogens in the past
Another use of dead specimens is to detect pathogens from the past.
“We can now take a piece of tissue from a specimen, extract the DNA, and in that DNA find a potential DNA of a pathogen,” stated Dr Wimberger.
To discover the origins of the Human Immunodeficiency Virus (HIV), researchers found that dead sooty mangabeys (Old World monkeys) collected in 1938 at The Smithsonian Institution tested positive for the simian immunodeficiency virus (SIV).
They concluded from this finding that SIV had been transferred to the human host and is close related to human immunodeficiency virus type 2 (HIV-2), a subtype of HIV which affects humans now.
3. To extract stable isotopes for diet study
Dr Wimberger stated, “You are what you eat and drink, thus your isotopic composition reflects the food you eat and the environment condition in which you’re in.”
By extracting the stable isotopes from dead specimens, scientists today can deduce the animals’ trophic position in the food chain.
An example of case is using Nitrogen isotopes to look into the diet of seabirds. Scientists managed to extract stable isotopes from the feather of preserved seabirds collected at the museum.
According to him, the higher the nitrogen isotopes ratio found in a specimen, the higher the specimen’s position on the food chain.
“Study after study, they have been using dead specimens from museum from the last 100 or 50 years, it shows that they have been rapid decline of nitrogen isotopes ratio for the last 30 years,” he said.
This means seabirds are now eating more organisms down the food chain such as crustaceans compared to the past where studies revealed they were eating organisms higher up in the food chain like fish. This is most probably due to decreasing fish populations today.
4. To determine effects of contaminants
Back in the 1960s, Bald Eagles and Peregrine Falcons were disappearing. Crushed eggs were found in nests meaning these eagles’ and falcons’ eggs had cracked before they could even gestate and hatch in the first place.
The thinning of the eggshells was linked to the use of DDT (dichloro-diphenyl-richloroethane) in pesticides used in 1940s and 1950s. At the time, DDT manufacturers argued there was no strong evidence to proof that DDT was the reason behind the thinning of these birds’ eggshells.
Scientist went back to the museum and started measuring the thickness of eggshell specimens from the 1900 to 1970s.
Their findings were startling yet expected: after 1945, eggshells became thinner and more likely to break and one suggested cause was the DDT in insecticides.
In the end, the use of DDT was banned in 1972 except under the public health exemption to suppress flea vectors for bubonic plague.
Dead specimens in the museum are not just stuffed animals; they are time capsules carrying genetic information that can help solve our present, give us a vision of the past and opportunities to discover more about our future.