Archive | April 2017

The Square

So you probably know by now that season 10 is up and running and there have been some amazing camera-trap images uncovered already. As well as a few lounging lions and wandering wildebeest there have been some stunning aardvark and wildcat images.

This season has turned up quite a few images with a central square that is brighter than the rest of the frame with a luminous look. These somewhat Warholesque images look as though they have been photo-shopped and I love them. Here are just a few. My favourite is the zebra, its perfect.

585915b3d369fd0040076a9d_1

Warthog backside

 

58591529d369fd0040071aab_0

Tree with Landrover

 

58591544d369fd00400729f3_0

Zebra

 

5859088cd369fd004000081b_0

cheetah

 

Obviously these are not some new form of art but have a more down to earth source; a malfunction with one of the camera trap types. A patch provided by the manufacturer restores the image to normal which for scientific purposes is very good but from the purely aesthetic side its kind of sad, I like “The Square”

 

 

Topi versus Hartebeest

Here is another pair of antelope that are often muddled up on Snapshot Serengeti; topi and hartebeest. These two share a similar size and body shape and for those of you not familiar with them they can prove a bit tricky.

Topi and hartebeest belong to the same tribe, Alcelaphini, which also includes wildebeest. These antelope typically have an elongated face, long legs, short necks and stocky bodies. Although these antelope have reasonably large bodies their long legs mean they have retained the ability to run fast, a good adaptation for life on the open plains. It is believed that the long face developed in place of a long neck in order to reach the grasses they consume.

There are several species of both topi and hartebeest in Africa, two are found in the Serengeti. Coke’s hartebeest or kongoni (Alcelaphus cokii) are selective grazers with browse making up less than 4% of their diet. Serengeti topi (Damaliscus jimela) are 100% grazers

In both species males are territorial but topi also form leks from which to display to passing females. Males holding territory close to the lek are more desirable to females. Dominant females will actively prevent subordinate females from mating with these males.

 

Topi                                                         Hartebeest

So side by side we can see that the topi is much darker coloured than the hartebeest with distinct sandy socks up to its knees and conspicuous black patches on the thighs and shoulders. In contrast the hartebeest has pale legs and underbelly with a darker upper body. The paleness forms a patch on the top of the thigh.

 

Topi                                                                        Hartebeest

From behind the contrast between leg colour and backside is very obvious with topi sporting dark legs with pale rump and back and hartebeest pale legs and rump with dark back.

Horn shape is also different. A topi’s horns sweep up and back whereas a heartebeest’s sweep out to the side before kinking back. They also sit on a prominent bony ridge on the top of the head.

Hopefully this will help you tackle all the images waiting on season 10.

Grant’s Verses Thompson’s Gazelle

 

The Zooniverse team are super busy at the moment but hopefully very soon season 10 will be loaded and we can all get cracking with what promises to be a fantastic season full of amazing images.

In the meantime I thought I would post a few notes on those tricky animal pairings that seem to have more than a few people stumped when trying to id them.

To kick it off we will look at Grant’s gazelle and Thompson’s gazelle. If you were treated to perfect photos every time I think you would get the hang of these two pretty quick but with the often blurry or distant images we get on snapshot they can be tricky.

 

Grant’s gazelle A                        Thompson’s gazelle A

 

A; First off there is the overall colouration. Thompson’s has a thick dark stripe across its side, Grant’s usually lacks this but be aware as some Grant’s have a dark stripe too. Not the best distinguishing feature as there can be quite a bit of colour variation.

 

Grant’s gazelle B                          Thompson’s gazelle B

 

B; A better distinction is the facial markings. Grant’s gazelle has a thick black stripe running along the side of the face from the nose passing through the eye to the base of the horns giving a masked look. Thompson’s has the same stripe but it ends at the eye, not passing through. The white band on top of the black stripe is more distinct on Grant’s.

 

Grant’s gazelle C                                  Thompson’s gazelle C

 

C; If you get a back-side shot then Grant’s displays a much whiter overall appearance with the white area extending past the root of the tail up onto the back. In Thompson’s the white area stops at the root of the tail. Grant’s tail is white at the root and thin with whispy black end, Thompson’s is dark and fluffy looking. The black vertical bands in Grant’s are also more prominent.

 

Grant’s and Thompson’s Gazelle

5144149140_35e79d6f19_b

Photo NH53, Flickr (https://creativecommons.org/licenses/by/2.0/)              

In a mixed group the smaller size of Thompson’s is evident, although with young animals it is not so obvious.  Here you can easily see most of the features discussed above with the Grant’s gazelle comprising the 7 animals to the right back and the Thompson’s gazelle to the left forward. Note the Grant’s gazelle side on at the back, it shows a much darker side stripe than the others more a kin to Thompson’s. Males and females of both antelope have horns with the females usually shorter and thinner. In some females horns are absent. In general Grant’s are more graceful looking than the stocky Thompson’s.