IELTS LISTENING – ANIMAL SENSE S55T4

However some animals have a sense of smell that is far more powerful than ours, dogs for example have a sense of smell that is 40 times greater than a human’s and can distinguish 220 kinds of smell. Some animals can even smell odors that are undetectable by the human nose, such as _Q31 carbon dioxide. There are also animals that have a relatively weak sense of smell. For example, there are species of beetles that can recognize the odors of certain plants but not others. The bee is an interesting example to examine in reference to smell because they experience this sense via their antennae.

Bumblebees have stings but it’s rare that they actually use this weapon .when a bee feels threatened it will use its _Q32 legs to signal and warn others about the threat before it stings. This is called a signaling posture and involves the bee lifting its two back legs into the air. Within any hive there is a hierarchy with the queen bee at the top, the queen bee is able to _Q33 control the colony by monitoring its movement through her feet. The queen bee is the only reproductive female in the entire colony and she is also able to sting multiple times, unlike the worker bees that will die if they sting. In the insect world scent can also be used to facilitate mating as females decide whether or not to mate with a male depending on the quality of his scent. One such example of this is the female _Q34 butterfly who will only mate with the male butterfly that produces the strongest pheromones.

 

This is how the species ensures that only the best genes are perpetuated in order to create the strongest offspring. Next, we move on to the hearing sense of beetles interestingly beetles do not have ears but instead use their _Q35 feet to detect vibrations caused by sound. This is particularly useful when searching for food among the trees in which they live as they are able to detect the location and movement of their prey by monitoring vibrations in the _Q36 woodlands. The final sense that we’ll be looking at today is sight, snakes are a particularly interesting case study as they do not see shapes and colors as humans do but instead hunt their prey by detecting the  _Q37 heat radiating from their mouths. This makes them incredibly effective predators as they are able to zero in on their prey very quickly and efficiently. From a distance a snake is able to locate the heat radiating from a mouse for example and upon moving closer will be able to determine its _Q38 bodyshape. This can help prevent the snake from attempting to attack prey that is too large for it. Once a snake has killed and eaten its prey it goes into a state of hibernation. Whereby all of its energy is directed towards digesting the food stored in its _Q39 stomach. Depending on the size of the snake and its prey this hibernation can last from hours to days.

Once fully fed a large snake will not need to eat again for the next couple of weeks. During the breeding season however female snakes will feed more frequently. The heat detection of a snake is very complex and can be even more effective than the vision of a human. It not only uses heat to determine the location of its prey but before it commits to hunt it will also use the heat to calculate how much _Q40 distance it has to travel in order to reach it. This prevents the snake from wasting energy hunting prey that is too far away to catch.