Bubble net feeding feed in a short amount of time. Humpback whales have a vertical throat roughly the size of a grapefruit. They cannot physically swallow anything larger than that. They are carnivores and primarily feed on small fish such as krill, juvenile salmon, and herring. They are also baleen whales, which means that they do not have teeth, so they must be able to eat things that they can swallow whole. They have several vertical grooves running down the length of their body so that they can hold large volumes of water and fish at one time. They feed for up to
Baleen whale Adults normally start reproducing when 5–10 years old and reach their full length after 20–30 years. In the smallest rorqual, the minke whale, calves are born after a 10-month pregnancy and weaning lasts until it has reached about after 6–7 months. Unusual for a baleen whale, female minkes (and humpbacks) can become pregnant immediately after giving birth; in most species, there is a two-to-three-year calving period. In right whales, the calving interval is usually three years. They grow very rapidly during their first year, after which they hardly increase in size for several years. They reach sexual maturity when long.