Coming from the past

30 03 2012

“For the majority of us, the past is a regret, the future an experiment”

– Mark Twain

Even the migration is stopped, I am still in a biodiversity paradise and it’s not worth to forget about that. The islands contitute huge evolution laboratories and the forces acting in the species ways are more noticeable in that ecosystems. Probably one of the first things Darwin observed as soon as he reached the Galapagos was the swimming iguanas. Reptiles have been always considered one of the oldest forms of vertebrate life and it’s possible to be aware of that just by looking at them. The colonization of an island depends mainly on 3 factors: the distance from another land mass, the age and the size of the island.

The Canaries are an heterodoxous group of islands. Not all of them emanated from the sea at the same time and the habitats are also extremely different between each other. That fact culminates in a complex phylogenetic tree of the genus Gallotia, endemic from the Canaries, already described by some works such as Thorpe 1994. The genus is represented by 2 species in Tenerife, althought one of them is very scarce and restricted to the northwestern corner. The other, Gallotia galloti, is present in most of the areas and you can get good views of it if you wait for a moment near a wall or even near an Opuntia plenty of fruits. Its diet is extremely variable and it can goes from insects to fruits. The size of the head and specially the size of the jaws is correlated with the diet and it shows a high sexual dimorphism very useful when sexing some individuals with a female-like colouration.

Yesterday, while waiting for a Barbary falcon couple in a typical cliff surrounded by tabaiba bushland, lots of lizzards were sunbathing and I felt it was time to look at them finally. The males are impressive, althought some of them are not as brightful as others are. Note the extremely prominent pterygoid muscle, in contrast with females.

Females are more approachable. One of them was moulting its skin. It does so part by part, not like snakes do. The head profile is slimer and jaws are not as powerful as in males.

Finally, the falcons appeared and I returned to my birding routine…




Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: