...the male
narwhal's tusk can be up to 3.5 metres in length which is over the size of an average female without a horn and weigh up to 10 kilograms.
...male narwhal(e)s tusk is the canine growing through the lip. Sometimes, the male will have 2 tusks but their number is small. Female narwhal(e) rarely have a tusk and if they do, it must be smaller than the males. Also,there is only 1 recorded case of a dual horned female narwhal(e)
...observations of cetaceans date back to at least
the classical period in Greece, when fisherpeople made notches on the dorsal fins of
dolphins entangled in nets in order to tell them apart years later.
...groups of
bottlenose dolphins around the Australian Pacific have displayed basic
tool use by wrapping pieces of sponge around their beaks to prevent abrasions. This is a display of a cognitive process similar to that of
great apes.