n.独角鲸(生活于北极地区，雄性有一长牙)

The narwhal is a medium-sized whale that possesses a large "tusk" from a protruding canine tooth.
长牙鲸是一种中等大小的鲸鱼，它具有一根从突出的犬齿长出的大“獠牙”。
Narwhals are found in the Arctic waters and are known for their spiral tusks.
长牙鲸生活在北极水域，以其螺旋形的獠牙而闻名。
Scientists have long been puzzled by the function of the narwhal's tusk.
科学家们长期以来对长牙鲸獠牙的功能感到困惑。
Narwhals can dive to great depths, up to 1,500 meters, to hunt for food.
长牙鲸可以潜入深达1500米的深度寻找食物。
The narwhal's tusk is actually a sensory organ used for detecting changes in its environment.
长牙鲸的獠牙实际上是一个感觉器官，用于感知环境的变化。
Narwhals live in pods and communicate with each other using a series of clicks and whistles.
长牙鲸以群体生活，并通过一系列点击声和哨声相互交流。
The population of narwhals is estimated to be around 80,000 individuals worldwide.
全球长牙鲸的数量估计约为8万头。
Narwhals face threats from climate change, hunting, and pollution in their natural habitat.
长牙鲸在其自然栖息地面临着气候变化、捕猎和污染的威胁。
The tusk of a narwhal can grow up to 3 meters in length.
长牙鲸的獠牙可以长达3米。
Conservation efforts are crucial for the survival of narwhals and their Arctic ecosystem.
保护工作对于长牙鲸及其北极生态系统的生存至关重要。