Consider the following animals: 1. Sea cow 2. Sea horse 3. Sea lion Which of the above is are mammal / mammals?

Based on biological classification, sea cows and sea lions are mammals, while sea horses are fish. Sea cows, which include manatees and dugongs, belong to the order Sirenia and are large, herbivorous aquatic mammals [4]. Sea lions are classified as pinnipeds within the order Carnivora; they are eared seals that possess paddle-shaped flippers and return to shore for breeding [2]. In contrast, the sea horse (genus Hippocampus) is a vertebrate species belonging to the class Actinopterygii, making it a bony fish rather than a mammal [1]. Sea horses are closely related to pipefish and seadragons and lack mammalian characteristics such as mammary glands or hair [1]. Therefore, only the sea cow and sea lion qualify as mammals, making option 2 the correct choice.

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 12: Animal Diversity of India > r:2..2.2, Herbivorous Marine Mammals > p. 189
2. [3] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 4: BIODIVERSITY > x) not evaluated (ne) > p. 16
3. [4] https://www.nhm.ac.uk/discover/what-is-a-sea-cow.html
4. [2] https://www.ncbi.nlm.nih.gov/books/NBK236689/