It took me many years to understand how animals names work, especially the Latin side of it all. But after learning it I realised it's not as complex as I first thought. You may be forgiven for thinking that every animal has a common name, this is not the case. Some animal groups are so numerous and similar that they are simply known by their Latin (binomial) name. For instance there are around 8,000 species of centipede, most do not have a common name.
The simplest part of animal naming is to understand that all animals have a scientific name. This is sometimes referred to as the binomial or Latin name. The name is made up of two words, for example the Lions scientific name is Panthera leo. The word Panthera refers to it's genus (which it shares with the Jaguar, the Tiger and the Leopard). The second word leo refers to its species.
Panthera leo – Lion
Panthera tigris – Tiger
Panthera onca – Jaguar
Panthera pardus – Leopard
So all 4 cats are in the same genus but are different species. With that in mind I want to explain duplicate names. An example is the Common Red Fox (Vulpes vulpes). As it is the most common fox in it's genus it has a double-word name. Other examples would be the Common Toad (Bufo bufo) and the European Badger (Meles meles).
So what are subspecies? Well a subspecies is a population of a species that differs genetically or physically from the 'norm'. Tigers are a great example of this. The main 'form' of tiger, the description that they were first described on, is called the nominate subspecies. In the tigers case it is the Bengal Tiger (Panthera tigris tigris). Note firstly that subspecies have three words to their scientific name. Broken down it translates as follows:
Panthera – Part of the large cat genus
Panthera tigris – Part of the Tiger species
Panthera tigris tigris – The Bengal form of the tiger species
The nominate subspecies has the middle and last words in their scientific name the same (i.e. tigris tigris)
In a nutshell that is how animal naming works. A few other things to point out are that, due to nomenclature ruling, the first correct name is used (so if anyone describes the same animal afterwards the second name is invalid). The only exception to this rule is if any new research determines that the genus is wrong and thus changed accordingly (For example the Polar Bear used to belong to the genus Thalarctos, but later research showed it was closer to true Bears and was re-categorised in the Ursus genus). Another variation on naming is colour forms. Sometimes a species may have two or more common colour variations. See the example below:
The Miller is a moth with two colour forms. These forms are known as Acronicta leporina c.grisea and Acronicta leporina c.melanocephala. Although they are the same species (not subspecies although their name has 3 scientific words) they share two different shades of colour. The tip to tell that grisea refers to a colour form and not a subspecies is the prefix of c. meaning simply colour.
Why do we use scientific names? The reason is simply due to ease of identification. Some animals may share the same common name, and some common names are misleading. For instance the Koala Bear is not a bear, the Bearded Dragon is not a dragon and the Slow-worm is not a worm! So scientific names can help describe the animal. Words such as gigantea (big, large), grisea (grey) and albocollaris (white-collared) all help describe the animal.
Other uses for scientific names can be to describe the animals location or discoverer. For instance the Japanese Red Fox is named as Vulpes vulpes japonica. So this scientific name tells us that the animal in question is a fox, the most common fox, and that it is the Japanese variant.
For hybrids the male species prefixes the females. For example the offspring of a Lion and Leopardess (Lipard) would have the scientific name Panthera leo x Panthera pardus.
Latin/scientific names seem awfully daunting at first but once you learn the basics, you begin to understand them a lot better. After all if every animal in the world shared the same common name, we would never be able to distinguish between anything!