Despite the tens of thousands of whale-watch hours each season, as well as the presence of multiple researchers for over thirty years, a birth has not been documented. At the same time, the following evidence support the assumption that humpbacks do give birth during the migration and winter months in Hawaii: 1. Studies from whaling operations clearly show that term fetuses and birth coincide in winter months; 2. In Hawaii, observations of tiny calves with folded dorsal fins and crease marks (clearly within days if not hours of birth) are common; 3. A humpback whale placenta was found in Hawaii shortly after a very young calf appeared beside an adult; 4. One study reported the sighting of a photo-identified female without a calf on January 31 (1981) and with a calf seventeen days later on February 16 (1981), indicating a birth had occurred.
The Mom/Calf Relationship
Since the birth of a humpback whale has not been documented, the specific behavior patterns of the mother immediately before, during and after birth are not known. It is likely that the mother’s behavior is geared towards rest, nursing and protection of the young. The last of these tasks may have three fronts: 1. Avoiding, or at least controlling, interactions with sexually active males; 2. Avoiding interactions with other mothers with a calf and; 3. Guarding against potential predators. These three goals may account for much of the behavior of mother/calf pairs such as their frequent travel and their tendency to stick to the shallow, inshore waters, ostensibly to avoid harassment from males and predators.
Despite our limited knowledge, it is obvious that the bond between mother and calf is a close one. Calves rely on their mothers for food and protection and are rarely seen far away from them. They accompany their mothers across the North Pacific to distant feeding grounds and it is not until a year after their birth, either on their migration back to the breeding grounds or once arrived, that the maternal bond is broken between the mother and now juvenile whale.