An important part of homeostasis is to control our blood sugar levels. But is it just humans who like sweet things?
Many humans have a sweet tooth, and some say that sugar is as addictive as drugs, although in a very different way. It is not only humans who are partial to sugar. Studies show that many omnivores enjoy the taste. However, carnivorous animals seem to have evolved so they have no taste receptors for sweet foods. As they do not ever eat anything sweet, they have lost the ability to taste it! Scientists investigated a number of carnivorous species to find out whether they had a mutation in their sweet taste receptor gene, stopping it working.
In some of these species, for example, the spectacled bear, the gene had not mutated. Further experiments involved offering them sugar water or plain water. The bears clearly preferred the sugar water. More of the species tested did have mutated sweet taste receptor genes, including otters. The same test was carried out – and the otters had no preference at all for plain or sugar water.
It does appear that not all sugar loving animals are as keen on sugar-replacements though. Rats and mice will happily eat sugar containing foods, or saccharin (a sugar replacement). But they do not like aspartame – a sweetener in many diet drinks. Wallabies are able to detect and enjoy glucose, sucrose and fructose, but were indifferent to any sugar substitutes.
And spare a thought for animals like the dolphin or sea lion. Not only have they lost the ability to taste sweet things, but they also cannot really taste bitter foods. In fact the sea lion has virtually no taste buds at all. Not that this would bother them much – as you will not see either animal savouring their food. Instead they swallow fish whole!
To help you understand how we manage the levels of glucose in our blood, check out Part 2 of our “How to” revision guide on Homeostasis. This guide concentrates on blood glucose regulation in the body.
It explains:
This will help if you are studying for GCSEs. It is also suitable for A Level students, as sections of the guide go “beyond GCSE”. It includes some example GCSE and A Level questions with answers at the end, so you can check your understanding of blood glucose regulation.
Click on the picture below to view our guide.
If you found this useful and think you would benefit from some additional help please contact us.
We welcome guest bloggers.
