true seal
Học thuậtThân thiện
Definition
Noun 1. A type of seal (earless seal): A "true seal" is a marine mammal belonging to the family Phocidae. It is characterized by the absence of external ear flaps, a streamlined body covered with short, stiff hair, and hind limbs adapted into swimming flippers that are not useful for walking on land.
Usage
The term "true seal" is used in zoology and wildlife contexts to distinguish members of the family Phocidae from other marine mammals like sea lions and fur seals (which have external ears and can use their flippers for walking).
Examples
- The harbor seal is a common true seal found in coastal waters of the Northern Hemisphere.
- Unlike sea lions, true seals move on land by undulating their bodies.
- Scientists are studying the diving patterns of the Weddell seal, a remarkable true seal of Antarctica.
Advanced Usage
- The term is often used in comparative biology: "The primary anatomical difference between a true seal and an eared seal is the structure of the ear and the mobility of the hind flippers."
Variants and Related Words
- Earless seal: A direct synonym for "true seal."
- Phocid: The scientific adjective or noun form referring to a member of the family Phocidae.
- Seal: The broader term that can include both true seals (Phocidae) and eared seals (Otariidae).
Synonyms
- Earless seal
- Phocid seal
Antonyms / Contrasting Terms
- Eared seal: Refers to seals in the family Otariidae, such as sea lions and fur seals, which have small external ear flaps.
- Sea lion: A specific type of eared seal.
- Fur seal: Another type of eared seal.
Noun
- any of several seals lacking external ear flaps and having a stiff hairlike coat with hind limbs reduced to swimming flippers