biology zoology blog Fathers milk lactation

Father’s Milk

Father’s Milk – a thing of the future?

In an encyclopaedia of 1909, I found the statement that the only mammal in which males are known to regularly supply milk to their offspring was a snowshoe rabbit in the Rocky mountains by the name of Lepus bairdii. Apparently this claim could not be substantiated later on, for the current view is that in spite of the presence of the nipples in many mammalian males, no male is known to normally lactate on a regular basis (but wait!). A combination of oestrogen treatment and nipple stimulation can, however, provoke lactation in male individuals of a wide range of animal species and spontaneous lactation, even in human males, is known. That male and female breast tissues aren’t terribly different is also borne out by the sad, but little known fact, that men, too, can suffer from breast cancer.

biology zoology blog frog egg embryon (1)

A Frog’s Egg

What can a frog’s egg teach us

Hardly anything in zoology could be more exciting than to observe how from an egg cell a whole new individual develops. Unfortunately for the curious person very often the developing egg is hidden from view as in mammals and sometimes it is so small that it is impossible to examine what precisely goes on. But there are some animals which allow even children without the aid of a microscope to observe the embryo and how it grows inside the egg. One example are freshwater pulmonate snails like Planorbarius corneus (the ramshorn snail) or Lymnaea stagnalis (the common pond snail). Their eggs, attached in clusters of up to 40 or so on the glass walls of an aquarium make observations easy. But other, and even bigger and therefore more suitable eggs allowing one to follow the changes that go on inside them are those of frogs, toads and newts. In the gelatinous eggs of these amphibians, rice grain sized in newts but up to the size of peas in frogs, one can see the entire developmental process through the transparent egg membranes virtually with the naked eye (although a hand lens would help, of course).