South Africa Diaries: Day 5
5am wake up this morning, and we headed up into the mountains to do some insect surveying. We saw a large bull giraffe when we were up there, and learned that giraffes are not territorial animals and have very loose social structures, much like humans. We started off our insect survey by doing ten sweep nettings, two meters apart. We didn’t catch a great deal, just a red locust, a yellow wing locust and a spider of some sort. The view from the top of the mountain however was magnificent.
We then headed back down the mountain, seeing some mountain reedbuck and baboons along the way, and did some tree beating to collect insects. We caught another spider and a few different species of beetle. We also identified some species that we found on the ground including a giant ant (Streblognathus genus), a greenmilk weed locust, a bont tick, an elegant grass-mimicking grasshopper, and a flower assassin (which gets its name from being highly predacious). It was apparently a diseased assassin bug that killed Charles Darwin. The green milkweed locust is a large species reaching up to 7cm in length. Its wings, when opened, showed a beautiful display of colours, which is thought to confuse predators after it has taken flight.
On the way back to camp, we spotted an African monarch butterfly, which gets its toxicity from eating milkweed. Any animal that has previously eaten one knows not to eat one again, so several other butterflies carry out Batesian mimicry to look like the African monarch butterfly and avoid being eaten themselves. An example is the viceroy butterfly (Limenitis archippus). We also saw a troop of vervet monkeys. Males have bright blue testicles, which they show to other males when challenging each other! We also saw a purple-crested turaco, kudu, red-billed oxpeckers, and a narina trogon.
At about 3:30pm, we went on a game drive and saw some impala, brown-hooded kingfishers, helmeted guinea fowl, honey guiders, grey-headed bush shrike, grey duiker, and we also heard some helmeted shrike. We also visited black leopard camp, which is the more luxurious accommodation in Thaba Tholo for tourists to stay. On the way back, we saw some scrub hare, bats, gemsbok, a lesser bushbaby, and a zebra. We also learned the difference between a hare and a rabbit - baby hares are independent from birth (precocial), whereas baby rabbits depend on their mothers for a while after birth (altricial).
Species Of The Day: Vervet Monkey
The vervet monkey, Chlorocebus pygerythrus, is a species of old world monkey native to most of southern and eastern Africa. It is very abundant but patchily distribution, possibly due to the fact that it needs to drink water every day. It is classified as least concern on the IUCN Red List, particularly because it is so good at adapting to new environments. It doesn’t have any threats, other than humans who often shoot them because they are classed as vermin.
There have been many studies looking into communication between vervet monkeys, including one which looked at semantic communication. Semantic communication is when different signals are given that stand for different things. Vervet monkeys were found to give different alarm calls depending on the predator, such as a snake or leopard. Other vervets can then comprehend this and act accordingly. However, it was also found that there is significant overlap in the sounds of these signals and aggressive calls, particularly in females.