Consider the following animals:
- Sea cow
- Sea horse
- Sea lion
Which of the above is/are mammal/mammals?
- 1 only
- 1 and 3 only
- 2 and 3 only
- 1, 2 and 3
Explanation
Sea Cow is correct
- The dugong, often called the “sea cow,” is the only marine mammal that exclusively feeds on plants.
- Dugongidae Family: It is the only surviving species in the Dugongidae family. Their close relative, Steller’s Sea Cow, was hunted to extinction in the 18th century.
- Physical Adaptation: Its cylindrical body, paddle-like flippers, rounded snout, and muscular upper lip are adapted for grazing on seagrass beds.
- Demographic Vulnerability: Dugongs can live up to 70 years but reproduce very slowly. Calves are born only every 3 to 7 years.
- Preferred Habitat: They thrive in warm, shallow, sheltered coastal waters less than ten meters deep. Dense seagrass beds provide food and shelter.
- Dietary Impact: An adult dugong consumes 30 to 40 kilograms of seagrass daily, which helps keep seagrass meadows healthy and prevents sediment overgrowth.
- Global Distribution: Dugongs inhabit warm waters of the Indian and Pacific Oceans, with a major population in northern Australia and the Arabian Gulf.
- Indian Range: A small population is found in Palk Bay, Gulf of Mannar, Andaman Nicobar Islands, and Gulf of Kutch. They are extinct in Odisha and Andhra Pradesh.
- Ecosystem Role: By grazing continuously, dugongs act as “ecosystem engineers.” They support seagrass health, help fish nurseries, and maintain the coastal food web.
- Primary Threats: Gillnet entanglement, vessel collisions, habitat loss, and illegal hunting.
- Conservation Status: IUCN: Vulnerable; CITES: Appendix I; WPA: Schedule I.
Sea horse is incorrect
- The sea horse is a type of fish, not a mammal. It belongs to the genus Hippocampus. There are 46 species of seahorses reported worldwide. The coastal ecosystems of India house nine out of 12 species found in the Indo-Pacific, one of the hotspots of seahorse populations that are distributed across diverse ecosystems such as seagrass, mangroves, macroalgal beds, and coral reefs. These nine species are distributed along the coasts of eight States and five Union Territories from Gujarat to Odisha, apart from Lakshadweep and the Andaman and Nicobar Islands.
Sea lion is correct
- The sea lion is a marine mammal belonging to the family Otariidae. They are part of the pinniped group that also includes seals and walruses.
- They live both on land and sea. Diet: Carnivorous.
- Physical properties: Streamlined body with brown or tan coat, large head, and long, flexible neck.
- Sea lion got its name because most males have manes. They roar to defend the females in their groups.
- They have external ear flaps, long foreflippers, the ability to walk on all fours, short and thick hair, and a big chest and belly.
- Habitat: Western coast and islands of North America, from southeast Alaska to central Mexico, on rocky shorelines, islands, and sandy beaches.
- The average life is 20-30 years. They can be as heavy as 1200 pounds.
- There are five species of sea lion: California, northern, southern, Australian, and New Zealand.
