Mothers, calves, escorts and competition pods

Birth

Gestation lasts about 11 months, which means a calf conceived in Maui in February is born in Maui the following January. Nobody has filmed a humpback birth in Hawaiʻi; the closest anyone has come is a newborn still trailing its umbilical cord. Calves arrive tail first, 13 to 16 feet long, about a ton, with floppy dorsal fins and a pale, wrinkled look that smooths out in a week. They can swim at once but not well, and for the first days the mother lifts the calf to the surface to breathe.

The first calves appear just before Christmas. By February they are everywhere. Look for a small blow next to a big one, close to shore in 50 to 100 feet of water, where the mother has gone to rest away from the males.

Nursing

A mother nurses for about a year, 100 gallons a day of milk so rich it is closer to cottage cheese than to cow’s milk. The calf gains around 100 pounds a day. She does not eat at all until Alaska, so by April she is visibly thin and the calf has nearly doubled in length. They leave Maui last, often in late April or May, and swim north together at the calf’s pace. The calf will stay with her for most of its first year and then separate. Females usually calve every two or three years.

Escorts

A mother and calf are often joined by a third adult, the escort, almost always a male. He is not the father (fathers play no role in raising calves) and he is not protecting the calf out of kindness. He is waiting: a female may come into estrus again while nursing, and he intends to be first in line. Escorts change over the season. When a second male arrives there is a fight, and a mother who has had enough will lead the calf into the shallows or roll on her back and tail slap until they leave.

Competition pods

When a receptive female moves through the channel she draws males the way a flame draws moths. The result, a competition pod or surface-active group, can hold two to twenty whales and is the most violent thing a humpback does. Males lunge over one another, blow screens of bubbles to blind a rival, throw their peduncles and slam their flukes. They bleed; the water goes pink and oily. The pod travels fast, and the female usually leads it, with the primary escort right behind and the rest fighting for second place. These groups form and dissolve within hours. If your captain finds one, stay with it.

Mating

No one has ever observed humpbacks mating, anywhere. We know the breeding grounds, the timing, the competition and the genetics (a female’s calves usually have different fathers), but the act itself remains undocumented. It is probably brief, probably belly to belly, and probably happens at depth or at night.

Where to see mothers and calves

• From shore: Papawai and McGregor Point lookouts in the morning; the Olowalu and Launiupoko shallows; Kāʻanapali Beach Walk in February and March, when mothers rest just outside the surf line.
• From the water: the small raft (Maui Whale Adventures) is the better choice for calves because it can idle quietly in the shallows where mothers rest and wait for a curious calf to come look. The catamaran’s height is better for seeing a competition pod coming from a distance.

Both operators follow the sanctuary’s guidance of extra care around mothers and calves: approach slowly from the side and behind, never between the two, and leave if the mother changes behavior.