Mother's Milk

Milk. For all young mammals, it is as essential for life as air to breathe.

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I was surprised to find that one of the cow elk my granddaughters harvested after Christmas were still lactating. I would have thought that calves were completely weaned this late in the year. By mid-September, calves have transitioned to mostly solid foods and can certainly survive without their mother’s milk, so late December seemed pretty advanced as that puts an added stress on their mothers who are trying to survive the oncoming winter and grow a new fetus as well.

Milk. It is one of the main distinctions between mammals and other creatures and is produced by modified sweat glands called mammary glands. All mammals nurse their young, even the egg-laying monotremes. The only difference there is that monotremes lack nipples and the young lap milk from patches of skin.

Milk is full of the sugar lactose, found only in milk and possibly a few tropical plants. Since all mammal babies drink milk, they produce lactase, the enzyme needed to digest lactose, in their small intestines.

Lactase is at its highest levels just after birth and declines slowly but steadily thereafter. Although we humans may think that giving milk to our adult dogs and cats is a nice treat, it isn’t. By adulthood, most animals cannot digest milk as their lactase production has dramatically dropped. For pets, a few tablespoons is okay, but a bowl full could make life very unpleasant for a while both for the pet and for the owner.

So, how do we humans consume milk in so many wonderful ways without discomfort? First, not every human does. There are many people who are lactose intolerant, likely because they do not have sufficient lactase production. For the rest of us, we can trace our ability to enjoy milk products to two things. First, processing milk into curds, cheese, yogurt and other products of fermentation, breaks down the lactose to a level we can handle. Second, according to Science magazine, around 6,000 years ago, a handful of genetic mutations that allowed humans to produce the lactase enzyme into adulthood spread quickly through human populations until almost everyone was affected.

Just as chefs have their own proprietary blends of herbs and spices for cooking, each species of mammal has its own exclusive milk chemistry. While there is still a lot of work to be done in this field, here are some interesting facts. Human breast milk and cow’s milk both contain about 3.5-4 percent fat, but cow’s milk has three times the protein. Both are around 87 percent water, but breast milk contains double the carbohydrates (including oligosaccharides which are complex sugars, not just lactose) of cow’s milk.

Other mammals have very different recipes for their milk depending on their needs. Hooded seal mothers produce the fattest milk known at 60 percent fat. In comparison, the richest ice cream has 16 percent fat. Seal pups need to grow fast and develop a thick protective layer of blubber and a diet of momma’s milk (up to 17 pounds, or two gallons, a day) has them ready for the environment in a record time of about four days. Alternatively, the black rhinoceros mother nurses her calf for up to two years. She has the least amount of fat in her milk at about 0.2 percent.

The diminutive eastern cottontail rabbit’s milk has been found to have the highest amount of protein, about 15 percent, of any animal tested, and it contains lots of fat as well. These little bunnies need to grow fast and they need to survive long periods between feedings, things the extra protein helps them do.

If you are looking for a sugar fix, look no further than the Tammar wallaby of Australia. Their milk contains about 14 percent sugar, double that of human breast milk and as much as a non-diet soda. This sugar is also mostly oligosaccharides.

Wallabies, like most other marsupials, can also control what goes into their milk, depending on the ages of their young. A wallaby mother may be nursing an older joey on one nipple with a fat-rich milk and an infant on another with milk high in carbohydrates.

So, for mammals, the question isn’t, Got Milk? It is, What kind of milk do you got (forgive the grammar)?

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Help Idaho Wildlife

When we traveled across the state in October 2017, most of the vehicles we saw using the wildlife management areas did not have wildlife plates. Buying wildlife plates is a great way for non-hunters and hunters alike to support wildlife-based recreation like birding.

C'mon folks, let's help Idaho's wildlife by proudly buying and displaying a wildlife license plate on each of our vehicles! 

See below for information on Idaho plates. Most states have wildlife plates so if you live outside Idaho, check with your state's wildlife department or vehicle licensing division for availability of state wildlife plates where you live. 

And tell them that you heard about it from Nature-track.com!

Wildlife License Plates

Great news! as of 2024, there are three NEW designs for license plates. They still are bluebird, cutthroat trout and elk, but they are beautiful.

Idaho Wildlife license plates provide essential funding that benefits the great diversity of native plants and wildlife that are not hunted, fished or trapped—over 10,000 species or 98% of Idaho’s species diversity. Game species that share the same habitats (such as elk, deer, antelope, sage-grouse, salmon, trout) also benefit from these specialty plates.

No state tax dollars are provided for wildlife diversity, conservation education and recreation programs. Neither are any revenues from the sale of hunting or fishing licenses spent on nongame species. Instead, these species depend on direct donations, federal grants, fundraising initiatives—and the Idaho Wildlife license plates.

Both my vehicles have Bluebird Plates. I prefer the bluebird because the nongame program gets 70 percent of the money from bluebird plates, but only 60 percent of the money from elk and trout plates - 10 percent of the money from elk plates supports wildlife disease monitoring and testing programs (to benefit the livestock industry) and 10 percent from cutthroat plates supports non-motorized boat access.

Incidentally, in 2014, the Idaho Legislature denied the Department of Fish and Game the ability to add new plates or even to change the name of the elk and cutthroat plates (very specific) to wildlife and fish plates, a move that would have allowed for changing images occasionally and generating more revenue. It would seem that they believe that we Idahoans don't want a well funded wildlife program.

I think it is time we let the Legislature know that Idahoan support wildlife funding and that we would like to see these generic plates come to fruition.