Humpback whale

Aliases Appearance Behaviours Diet Distribution Evolution Feeding Migration Navigation Nearest relatives Observer hints Parasites Predators Reproduction Social system Song Status Strandings

The sources of this information are provided under resources

Aliases

Taxonomic classification
Kingdom Animalia
Phylum         Cordata vertebrates
Class          Mammalia mammals
Order         Cetacea
Sub-order     Mysticeti baleen whales
Family       Balaenopteridae rorquals
Genus         Megaptera Mega - ptera : giant wing in reference to its flippers
Species         novaeangliae novae – angliae : of New England ; previously nodosa
Humpback whale noaa

Appearance

Male

Length: 12.2-14.6 m   (40-48 ft)**
Weight: 22.7-36.3 tonnes (25-40 tons)**

Female

Length: 13.7-15.2 m   (45-50 ft)**

General characteristics

Colouration

Distinguishing features

** different numbers are given by various authorities; I included them to give some idea of the dimension or scope of these features

Behaviours

For many of the humpback whale's repertoire of behaviours, there is no known explanation.  Below are the most widely-reported acts and some of the suggested interpretations or what is known of the behaviour. Breaching launches 2/3 of its body out of the water, head first; falls back with a splash, often rolling onto side

Flipper slap

Flipper waving

Head lunging

Head slap

Tail lobbing

Diet

What

Krill, sardines, mackerel, anchovies and other small schooling fish krill - a small crustacean like a miniature shrimp krill mating swarms can be huge - one hundred million tons

Where

In polar waters feed in the top 100m (330ft) of the water column, where there are dense swarms of suitable plankton

When

In the cold waters during summer usually feed twice a day; the first feed occurs at dawn and is the larger very occasionally in warmer waters feeding may resume during migration to the polar seas

How much

Estimates vary but the range per whale per day is 1.3 - 4.1 tonnes (1.3 - 4.0 tons)

Distribution

Evolution

As whales are mammals, they posses general mammalian characteristics like breathing air, bearing live young and suckling them, maintaining their own body heat.

They have evolved from land-living ungulates, hoofed mammals; the changes involved in this path include :

Feeding

Humpback whales feed by opening their mouths and taking in large volumes of water, as much as 2275 litres (500 gallons) at a time, causing the pleated grooves in the throat to expand. The whale uses its large tongue to force water out through the baleen plates which act as a sieve, and leave the prey trapped in the hairy fringes of the plates.

A number of feeding methods have been described:

Lunge feeding

Flick feeding

Bubble netting

  1. as the bubbles rise, the whale races through the bubbles with its mouth open
  2. appears to drive the prey against the bubbles and catch them as they retreat from the bubbles
  3. from below a concentration of prey, the whale circles slowly towards the surface blowing bubbles which eventually encircle the prey and prevent it from escaping; the whale emerges within the circle with its mouth open

Cooperative hunting

4-6 whales herd schools of prey and take turn lunging feeding

Migration

Pattern

Why

How far

Estimates of migration distances:

  1. round trip Alaska to Hawaii, 9500 kms (6000 miles)
  2. Antarctica to Australia 2500 kms (1500 miles)

Navigation

Nearest relatives

Family Genus Species Common name
 

Balaenopteridae

 

Rorquals :

  1. dorsal fin

  2. ventral pleats running from lower jaw to belly

Balaenoptera physalus Fin Whale
edeni Bryde's Whale
borealis Sei Whale
musculus Blue Whale
acutorostrata Minke Whale
Megaptera novaeangliae Humpback Whale

Observer hints

External fauna

Barnacles

Whale lice, Cyamus boopis

Penella

Sea Lampreys, Cookie-cutter Sharks

Remoras

Internal parasites

Predators

Reproduction

Competition between males

Signs of Courtship

Birth

Sexual Maturity

Social system

basic unit appears to be mother and calf ; this represents the longest association between individual whales

in the summer feeding grounds, the size of a group (1-20) will depend on the size of the prey patch

Song

Status

No special conservation status

global population increasing

World population estimates:**

5,000-7,000
15,000-20,000
representing 15-20% of the original population

Local population estimates:

Eastern Australia - 2000
North Pacific off Alaska - 2000
**I think the disparity between the estimates is due to the difficulty in making an estimation.

Strandings

Resources - books

These are just a few of the many sources of information available about the Humpback Whale