Inglés para adolescentes: 10 amazing facts about whales

¿Quieres saber unas cuantas curiosidades sobre las ballenas? Te invitamos a leer 10 amazing facts about whales elaborado por la redacción de la revista para aprender inglés I Love English.

Los estudiantes de Secundaria conocerán datos muy interesantes y sorprendentes sobre la vida y costumbres de una de las especies más fascinantes de los océanos, las ballenas. Además, aprenderán nuevo vocabulario y practicarán la lectura en inglés.

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10 amazing facts about whales (10 hechos increíbles sobre las ballenas) 

Las ballenas son seres únicos, gráciles y misteriosos: innovan, crean amistades, juegan, cantan y cooperan entre ellas. Aquí tienes algunos datos extraordinarios sobre ellas y su vida en los océanos.

1. Whales are mammals like us humans. They belong to the Cetaceans, along with dolphins and porpoises. There are about 90 different species worldwide. They use "sonar" or sound waves to navigate, find food, detect prey or objects and to communicate with each other. This is because sound moves four times faster in water than in air. 

2. Whales sing! A whale song is a complex, long, patterned sequence of sounds. Some of these sounds are unique to each individual, as if they had a particular name they use to identify themselves to others. The singing may serve as a way to advertise their position and communicate with one another many miles away, more than as a recreational pastime or to attract females.

3. Whales are divided into toothed whales and baleen whales. The key difference between them is the way they feed and what they eat. Toothed whales obviously have teeth; however, they don?t use them for chewing, but to actively grab large prey (like salmon), which they swallow entirely. Baleen whales, instead, have baleen plates, similar to "sheets", which serve them to "filter out" small prey like krill, plankton and crustaceans: the whale first takes a big gulp of water, then pushes it out through the baleen and the prey gets trapped in its mouth, making it easier for the whale to eat it.

4. Despite living in the water, whales breathe air. In fact, they are known as "conscious breathers", which means that they decide when to take a breath. But if they need to breathe consciously, how do they sleep? Well, they "shut down" one side of their brain to rest while the other side is alert to keep them breathing!

5. By the way, their super-sized brains can reach 500 cubic inches (about 13 cubic metres). This is five times the volume of human brains. Their brain can also weigh up to 9 kg (around 20 pounds), which is approximately the weight of a small dog and 6 times heavier than ours!

6. Their total size is equally amazing. Blue whales are the largest animals ever existed and can grow to about 90 feet (27 metres) ? as long as three school buses ? and weigh as much as 330,000 pounds (150,000 kg) or 24 elephants!, i.e. larger than any dinosaur! Their heart has the size of a small car!

7. Whales keep the ocean balanced and healthy. Their "poop" acts as a fertilizer for phytoplankton, which is comprised of tiny plants that produce 50-85% of the oxygen we breathe. That means that every breath we take contains oxygen produced by the ocean. 

8. Unfortunately, six out of the 13 great whale species are considered as endangered. About 300,000 whales and dolphins are killed each year. Loss of habitat, industrialization of oceans, commercial fishing, shipping, oil and gas exploration are some of the main threats to them.

9. Among the initiatives some international organizations are taking to protect them are: monitoring and mitigation of bycatch in fishing; reduction of underwater noise and collision risks from shipping; detection of threats and harmful practices in order to safeguard their habitats; and arrangement of campaigns to raise awareness among governments, industries and individuals.

10. Although orcas are known as "killer whales", they are not actually whales, but the largest species of dolphin!