Sunday, 9 May 2021

Miocene (Pt 26): Planet of the Monkeys

The primates are one of the major mammalian orders alive today, with a great many species spread across three continents: Africa, Eurasia, and South America. They have an ancient history, and, even by the dawn of the Miocene, were already divided into the two main groups we have today: the prosimians and the anthropoid primates (most of which are monkeys, or 'simians').

It's probably fair to say that most scientific attention has been paid to the latter of those groups, but we do have a number of fossil prosimians from the Miocene. Madagascar, where most prosimian species are found today, was already an island, and had been since the time of the dinosaurs, but there are few known fossils of the relevant age there to tell us much about the early history of lemurs and their kin. Nonetheless, during the Miocene, prosimians were more widely spread than they are today. 

Sunday, 2 May 2021

Mammals That Sense Magnetism

Traditionally, there are said to be five senses: vision, hearing, taste, smell, and touch. From a modern scientific viewpoint, however, this is clearly a significant underestimate, since things are rather more complicated than that.

How many senses even a human can be said to have is a matter of definition, although it's generally agreed to be more than five. An extreme way of counting would be to consider every specific type of sensory cell as representing one 'sense'. This, however, results in the conclusion that vision is four separate senses: one for black-and-white (the rod cells) and one each for the primary colours (the cone cells). This, it's probably fair to say, is not something that's widely considered helpful - although it may well be useful to neurobiologists.

If we don't go that far, then, we can still consider vision, hearing, taste, and smell to be singular senses. It is, however, not uncommon to consider the ability to sense temperature as distinct from the ability to sense that you are physically touching something. Pain can also be considered a distinct sense, since you can obviously 'feel' when you have, say, a headache, but it's hard to argue that that should count as 'touch'.