Just the thought of trying to get a chimp to sit still for a syringe when it could suddenly grab it from your hands, bite you, break the syringe, escape and climb away from your reach, or make use of an unpleasant projectile, makes working with pigs and rats seem a lot more appealing.

Not new species per se, but certain human traits and genetic variances are more recent than others. The ability to digest lactose in adults is thought to be a recent development, for instance (https://doi.org/10.1038/500020a). A trend happening in the past couple centuries or so is increased presence of the medial artery (https://doi.org/10.1111/joa.13224).

In linear algebra and other types of mathematics, the notion of perpendicular is generalized to "orthogonal" in different coordinate systems, with the idea that a certain type of "product" between two vectors (i.e. the "dot product" in our familiar cartesian coordinates, and more generally the "inner product") equals 0.

At a small enough scale we can treat the earth's surface as a flat plane and still get reasonable results, though on bigger scales we have to use a roughly spherical geometry. On a sphere you can still have two orthogonal axes for your coordinate system, just the path you travel affects what direction you end up facing differently from a plane. Triangles add up their angles differently from a flat plane, etc., but that only matters if you are traveling very far.

So there is one broader mathematical definition of perpendicular of which our coordinates on Earth are a special case. But why have we chosen perpendicular axes? Historically, perhaps because it's a simple and intuitive way of describing the geometry we can see and interact with. Sort of an emergent property of human thinking, when people in antiquity were working mathematics as it related to everyday experience. Humans seem to like symmetry and simplicity, so a four-fold symmetry of right angles is a "nice" coordinate system to us.

This and other answers speak to something much broader about the sciences and really, most branches of academia.

It's one thing for a potentially game-changing fact or new data to be identified or noted. The actual conclusions based on said data can take decades, or maybe reach no resolution at all, or the conclusions may change based on new analyses, etc.

Simplest answer to the first question (from a non-expert): mammals that regularly live in the open cold tend to have specialized fur coats. These are really good insulators. That and their metabolism probably works in favour of keeping them warm.

As to the second question, hunter gatherer societies can use the pelts of the animals they hunt, as well as build structures that minimize the amount of wind you have to deal with. Often involving animal hides again, or other kinds of shelter. If you've ever been inside a hollowed out structure of snow (i.e. a quinzee), it is relatively warm compared to having no shelter at all.

It might be noted that "species" is a pretty complicated construct with no clear answer as to where to draw the line between very similar species. In a certain sense, every species is always evolving. Yet the observable effects are hard to separate into discrete chunks without looking at these huge time scales.