How Do Springbok Keep Cool?

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Springbok (Antidorcas marsupialus) live in South Africa which, obviously, can get very hot during the day. Many animals that live in Africa tend to try and stay in the shade during the day to keep cool but there are also those that store heat in their body during the day and then let their body temperature decrease rapidly during the night so that the next day they can do the same again. This technique is called adaptive heterothermy and has been seen in often in captive animals. Fuller et al (2005) carried out a study to see whether this technique was also found in wild animals and decided to investigate a free ranging herd of Springbok.

For this study some very impressive technology was used to save time and also to make the results more accurate. Small data recorders where implanted inside each animal and these measured the body temperature of the animals every 30 minutes for a year. If this technology had not been used then the Springbok would have had to have been captured every 30 minutes, every day for a year. Not only would this be very time consuming, it would also affect the results of the study because the animals would likely be stressed about being caught all the time. While the animals were doing their own thing for a year, the team measured the temperature of the air, the wind speed and the humidity so that at the end of the year the body temperature could be compared with the weather.

If the Springbok used the technique described above then the body temperature would be expected to change often with very wide swings. They actually found that the opposite happened. No matter what the weather was like, the body temperature of the animals hardly changed. This technique is called homeothermy and it was a very surprising find. Even stressful events like giving birth did not affect the body temperature a great amount.

This study highlighted a very important point to consider when carrying out experiments on body temperature. When animals are roaming free in their natural environment they often use behavioural mechanisms to change body temperature instead of using physiological mechanisms such as adaptive heterothermy. Behavioural mechanisms like this include huddling together when it is cold or finding a shady area when it is too warm. Fuller and team made a mistake in this study because they did not watch the behaviour of the animals, they only took physiological measurements. Hopefully further studies will be carried out that will learn from this mistake!

References

Fuller, A., Kamerman, P. R., Maloney, S. K., Matthee, A., Mitchell, G. and Mitchell, D. (2005). A year in the thermal life of a free-ranging herd of springbok Antidorcas marsupialis. J. Exp. Biol. 208, 2855-2864.

A Decade Long Marine Census Comes To An End

Yeti Crab - Census of Marine Life

The Census of Marine Life which started in 2000 has finally been completed. It is estimated that during the census 20,000 new species have been discovered, bringing the number of known species to nearly 250,000. The decade long project cost £413m and aimed to find out what lived, lives and will live in the oceans. It involved more than 540 expeditions with over 2,700 researchers and used many new types of technology. Fish were tagged and seals were fitted with monitors to record when they dived. Acoustic systems were used to measure fish populations.

Dr Ian Poiner, the chairman of the project’s scientific steering committee, told the BBC “All surface life depends on life inside and beneath the oceans”. This is literally true because we know that life evolved from the oceans and the very first life forms were aquatic organisms. Back then the atmosphere did not have everything they needed to survive but the water did. It was a while before the air contained the nutrients that were needed but eventually life began to evolve on earth. It is thought that there could still be many undiscovered species in the oceans and there could be at least a million of them in total.

Many wonderful species have been discovered during this census, including a Jurassic Shrimp that has thought to have been extinct for at least 50 million years and a crab which has been named the Yeti Crab (see the picture at the top of this post). However, it wasn’t just large organisms that Dr Poiner’s project looked for. The census included trying to tell tiny microbes apart using genetic sequencing. If you thought that a million organisms was a lot then you will be surprised at how many different types of microbes are thought to be in the water – one billion. Hopefully the Census of Marine Life will serve as a base for us to build on to try and preserve marine life.

Source - MSN News