Hello again, welcome back to animals under threat. Today,
we will be covering the largest marine mammal currently alive today. Its
current geographical range covers all the oceans in the world and is under
threat from whaling. Please welcome the Blue Whale (Balaenoptera musculus).
Growing over 30 meters in length, the blue whale is
currently the largest marine mammal alive today. Feeding on its favourite food,
which is krill, the blue whale can weigh up to 200 tonnes (Britannica.com,
2019). Blue whales belong to the baleen whale family which means they have
fringed plates that contains finger-like material called baleen. The whale
swallows a mouthful of water and its tongue pushes the water through the plates
leaving the krill behind (nationalgeographic, 2019).
Unlike other whale species that live in pods, blue whale
prefers to live alone or in pairs. A blue whales call is a low frequency
whistle that reaches 188 decibels which is louder than a jet engine. This call
is useful for finding a mate in the ocean (wwf.org.au, 2019). Female blue whales
carry a calf for a year before it is born. The calf can weigh up to 3 tonnes
and 25 feet long when born and feeds on its mother’s milk, gaining 200 pounds
every day for its first year (Worldwildlife.org, 2019).
Blue whales are under threat from whaling, entanglement
of nets, pollution and global warming. Baby and juvenile whales are at risk of
drowning due to been caught in nets as they are unable to free themselves. Adult
whales are at risk from whaling as they are hunted for their meat due to their
size. Pollution from plastics has led to the whales dying due to the plastics
they ingested cannot be removed. Global warming has increased the temperatures
in the water which affects the whale’s food supply as the krill are dying due
to the temperature (Clapham et al, 1999).
Next time, we will be covering the largest carnivore in
the arctic circle and is considered to be the largest bear species to be alive currently.
References
Clapham, P.J., Young, S.B. & Brownell, R.L. 1999,
"Baleen whales: conservation issues and the status of the most endangered
populations", Mammal Review, vol. 29, no. 1, pp. 37-62.
Cooke, J.G. 2018. Balaenoptera musculus . The IUCN Red
List of Threatened Species 2018: e.T2477A50226195.
http://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T2477A50226195.en.
https://www.nationalgeographic.com/animals/mammals/b/blue-whale/
retrieved 11/12/19
https://www.britannica.com/animal/blue-whale
retrieved 16/12/19
https://www.worldwildlife.org/species/blue-whale
retrieved 16/12/19
https://www.wwf.org.au/what-we-do/species/blue-whale#gs.mmndbc
retrieved by 16/12/19
Picture references
https://en.wikipedia.org/wiki/Blue_whale
https://www.britannica.com/animal/blue-whale
https://au.whales.org/whales-dolphins/species-guide/blue-whale/
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