On a recent whale-watching trip, I asked one of the guides about how whales breastfeed underwater. His answer intrigued me, so I conducted further research on this when I returned to shore.
Whales have inverted nipples inside mammary slits. When the calf is ready to feed, they dive underneath the mother and nudge the mammary slits. The nipple is released, and the mother provides milk to the calf.
I found this interesting and wanted to find out some more information. If you want to find out more, please read on.
How Do Whales Breastfeed?
Whales have inverted nipples inside slits that hold the mammaries. When the calf wants to feed, they nudge the mammary slits from underneath, and the mother releases the nipple. When the nipple is removed, the whale rolls its tongue around it to drink the milk.
Many ocean mammals have evolved and developed unique mechanisms to survive in their environments. In the case of the whale, they need to breastfeed. Whales are surrounded by water, and breastfeeding in this environment is difficult.
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Do Whales Produce Milk?
Whales are sea mammals and possess the typical characteristics of all mammals. Whales have mammary glands and produce milk to feed their young. Milk has high-fat concentrations, essential for young whales to grow fat to keep them warm.
The calves require plenty of milk to grow and stay healthy, depending on the whale species. Generally, a young calf can consume approximately 10 percent of its body weight daily in milk. The blue whale is the most enormous; females can produce over 200 liters of milk daily.
Do Whales Have Nipples?
Whales do have nipples, but they are not extended on the outside as in humans. Nipples can also be found on most male whales as well. Whales spend their entire life inside the water, so nipples and breasts outside the body would not be the best place.
Whale nipples are enclosed within skin folds, referred to as mammary slits. Whenever a calf wants to nurse, it nudges the mammary slits, stimulating the mother to expose the nipples.
Whales have inverted nipples. This is not the same as terrestrial mammals that have protruding nipples. When the calf is ready to feed, they dive underneath the mother and nudge the mammary slits.
This signals to the mother that the calf is ready to feed and stimulates the mammary slit to release the nipples.
After stimulation, the whale lets out the nipples from the mammary slits, and the young calf wraps its mouth around it. This ensures that the milk is channeled directly into the mouth and that none of the milk is lost into the water.
The baby whales roll their tongue into a tube or U-shape. The rolled tongue is pressed onto the upper palate and placed around the nipple. The mother then ejects milk right into the mouth of the calf. The mammary glands have particular muscles that first contract, then shoot out milk directly into the mouth.
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What is The Consistency of Whale Milk?
Whale milk has a very thick consistency and is almost solid. The thickness is attributed to the high fat concentration reaching up to 50% fat in some whale species. The consistency and texture of whale milk is compared to that of toothpaste.
Whale milk tastes like a mix of oil, fish, liver, and milk of magnesia. It contains about 450 calories per 100 grams, with over 10% protein. Whale milk is not fit for human consumption due to its high-fat content. The color of whale milk can range from creamy color to greenish-yellow.
Whales produce large amounts of milk to sustain the survival of their young ones. The blue whale calf gains weight at a remarkable rate of 100 kgs in a single day. This means that it must suckle over 150 liters of milk a day. The liquid is also very rich in all the nutrients vital for the calf’s growth.
One of the main reasons whales can successfully breastfeed underwater is the milk’s consistency. Whale milk has an unusually high fat content of 35% to 50% fat in many species.
The high fat content makes the milk thick enough to pass through the water. Baby whales do not have lips and, therefore, cannot possibly nourish the same way as land mammals. High-fat concentration in the milk is necessary because the adult female whale can eject liquid into the calf’s mouth without dissolving it into the water around their lips.
Sperm whale calves feed differently from other whales. Sperm whales feed on milk orally rather than through suckling. Sperm whales release milk directly into the water, and the calves feed on the milk from the water.
Sperm whales have mouths that are not conveniently shaped to support suckling. Sperm whale calves can only feed on milk directly from the water.
How Long Do Whales Breastfeed?
There is only one breeding season for whales. The adult female whale mates with more than one male, increasing the chances of getting pregnant.
Female whales produce offspring every 1 to 5 years, although this depends on the species. The whales do not reproduce more often, allowing plenty of time for the calves to grow fully and increase their survival chances.
Lactation habits differ between baleen whales and toothed whales. Baleen whales breastfeed their calves for a shorter period, with a lactation period lasting between 5 to 7 months. During this time, baleen whales fast, eating only small amounts of food.
Toothed whales breastfeed for a longer period than baleen whales. Their lactation period can last between 1 to 3 years. The mothers continue to feed in the usual way.
Breastfeeding in whales continues until the calf is old enough to survive and hunt its food. At six months old, baby whales are usually weaned but may continue to breastfeed. When weaning begins, the amount of milk produced gradually decreases.
Breastfeeding creates a close bond between a mother and her calf. Sometimes a calf will continue to suckle on the nipple even after lactation stops. Some species of whale have mother-child bonds that last a lifetime.
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What is the Importance of Milk to Young Whales?
Like terrestrial mammals, milk is vital to a young whale’s existence. Baby whales rely on milk for healthy growth and nourishment. Newborn whales survive entirely on milk until they are ready to be weaned.
Without milk, baby whales would have low survival rates and starve to death. Typically, a newly born whale consumes large amounts of milk daily. Milk is their sole source of food at this time.
Whale milk is rich in all the nutrients required for the calf to grow well and thrive. The liquid is packed with healthy fats that provide energy for the rapidly growing calf. Other nutrients in the milk support bone development, boost the immune system, and ensure the brain’s proper functions.
Suckling milk creates an unbreakable bond between the mother and her calf. This is important in the development of the baby whale. Research has proved that the relationship between marine mammals and their parents is crucial for survival.
Marine mammals living in captivity have shorter lifespans than their counterparts in the wild. It is believed this is due to their inability to nurture naturally.
Whale milk contains a high concentration of fatty acids. The fat in milk plays a significant role in the development of fat. Blubber is a thick layer of fat under the skin of marine mammals, such as whales.
Blubber develops as a whale grows. Since whales spend so much time underwater, they need a mechanism to keep their body temperatures constant and prevent excess heat loss.
Blubber acts like an insulating layer against the cold from the water. The high-fat content from the milk enables the thick insulating fat layer to develop.
Do Whales Feed Other Calves?
The emotional and social relationship between whales and their calves is often unique. It is not common to find a female whale breastfeeding a calf other than her own.
However, some family groups are so close that they share the responsibility of caring for the young ones. In such pods, a female whale can breastfeed a calf belonging to another whale. This only occurs in some whale species.
References
Carwardine, M. (2017). Mark Carwardine’s guide to whale watching in North America : USA, Canada, Mexico, where to go, what to see. London: Bloomsbury.
Carwardine, M. (2010). Whales, dolphins, and porpoises. London: Dorling Kindersley.
Bernhard Grzimek, Schlager, N., Olendorf, D. and American (2003). Grzimek’s animal life encyclopedia. Detroit: Gale.
Hadoram Shirihai, Jarrett, B., Graeme Cresswell, and Kirwan, G.M. (2019). Whales, dolphins, and seals : a field guide to the world’s marine mammals. London: Bloomsbury Wildlife.
Martin, T. (1990). The illustrated encyclopedia of whales and dolphins. Hodder.
Nowak, R.M. and Walker, E.P. (1991). Walker’s mammals of the world. Baltimore: Johns Hopkins University Press.
Perrin, W.F., Würsig, B.G. and J G M Thewissen (2002). Encyclopedia of marine mammals. San Diego: Academic Press.
Richard John Harrison and Bryden, M.M. (1990). Whales, dolphins, and porpoises. London: Mercyhurst.
Williams, H. (1988). Whale nation. London: Cape.
Wilson, D.E. (1999). The Smithsonian book of North American mammals. Washington: Smithsonian Inst. Press.
May, J. (1990). The Greenpeace book of dolphins. London: Century.
Bryan Harding is a member of the American Society of Mammalogists and a member of the American Birding Association. Bryan is especially fond of mammals and has studied and worked with them around the world. Bryan serves as owner, writer, and publisher of North American Nature.