Humpback whales are born 10-20 feet long and can weigh 1-2 tons at birth. A full grown humpback whale (at the age of 12) could grow up to 45 feet long and weigh up to 40 tons, with the females usually being longer and heavier than the males. Their flukes grow to be nearly 20 feet wide - as long as their pectoral fins are and roughly the length of their heads. Nearly 40% of their weight is muscle! The largest humpback whale recorded was caught and killed in the Caribbean many years ago. She was 88 feet long. How much she weighed was unknown since they are taken apart before hauling on board. Some scientists speculate that humpbacks could theoretically continue to grow as they age. To this day, the largest humpback known is 50' long and weight most likely 50 tons. (They weigh a ton per foot.) Where did all the big ones go? The sad answer is they were probably taken by the whalers. It may take several generations before we have true answers.

Humpback whales can see well beneath and above the water since the colors change under water. Their brown eyes are perfectly adapted: lachrymal glands produce a fatfilm which protects the eye from saltwater. The lens is elastic and can be adjusted to the different light conditions by muscle power. Humpback whales can see up to 400 feet under clear water. They can also see equally well above the surface. According to research, cetaceans also have a tapetum, giving the eye the ability to reflect light back through the retina increasing the light available. This is especially important in low light conditions, but also important in water where things appear more blurry.

Although the rod-like and cone-like receptors are present in the eyes, according to researchers, the ability to discern colors in dolphin studies suggests that most likely the cetaceans cannot see in color. The data to explore color vision for baleen whales is greatly lacking.

If a humpback whale is coming to the surface to breathe after a dive, it exhales air with a speed of more than 300 m/h. The whales are utilizing about 90% of their lung capacity of 2500 gallons - in comparison with humans, which utilize about 15% when breathing normally! Their lungs are very large and when they exhale they force the warm air through a small sinus opening, forcing the air to cool in nano seconds (like air in a compressed can). This shows up as a tall vapor, which can be as high as 15', bushy to heart shaped for a humpback whale. The exhalation is also called spout, or blow. The inhaled amount of oxygen is "stored" in their blood and to 40% in their muscles which enables the whales to go as deeply as 600 feet or more and stay down up to 55 minutes (recorded in the feeding grounds). The whalers years ago knew that every species of whale had their own signature shape of exhalation and could tell from a distance what type of animal was traveling in the area.

Although humpback whales differ from their other family members in many ways, one characteristic that is the same with all six family members is the way the throat grooves, or ventral pleats, are situated. All of the baleen whales have 14 to 35 throat grooves which run from the chin to the navel. The main difference between the humpback and the other whales is that their flippers (pectoral fins) are unusually long - up to approximately 20 feet, which is up to a third of their whole body length. Therefore, they also have the scientific name Megaptera novaeangliae, which means "Great Wings of New England." The reason the flipper is so long is still a mystery, although scientists have learned that the pectoral fins, with the knobs on the leading edge, make for amazing control and turning abilities. More studies are being done on this subject.