About the cave
The Montagu cave (also called the Guano Cave) consists of a large, high chamber at the back of which is an opening to a smaller and longer tunnel-like cave once filled with bat guano. In the 1890s the guano was emptied out. Under the guano were found two important items a bored stone and a stick of olive wood with a rounded head at one end.
In 1964 an American archaeologist, Charles Keller, excavated and dynamited a third of the main chamber of the cave and found, buried among ash and red sand, several thousand artefacts shaped like spear-heads. His conclusion: that the cave was a factory site in which, some 20 000 to 50 000 years ago, hand-axes and other tools were made. Click here to read the full article which appeared in the Mail & Guardian on October 7, 1997.
The Bats
Some interesting facts about bats (Order: Chiroptera) More than 1000 species of bat are known worldwide and they occur on all continents except the Polar Regions. Each species has a unique lifestyle - and because bats make up almost 25% of all mammals in the world, they truly display extraordinary ecological diversity! For example, the largest bat in the world is the Golden-capped fruit bat which has a wingspan of at least 1.5 m; the smallest bat is the little bumblebee bat, which weighs only 2g!
Bats feed on a variety of foods including fruit, nectar, pollen, small vertebrates, blood and insects. But don't worry- African bats do not suck blood! Also, bats are not blind and they most certainly do not become entangled in your hair. All bats are nocturnal and they usually spend the daylight hours roosting in caves, rock crevices, trees or roofs of houses until dusk, when they leave the roost to start feeding. Therefore, these weird and wonderful creatures are often misunderstood, because we very rarely actually see them while they ago about their business at night.
Bats belong to the order of mammals called Chiroptera which means 'hand-wing' in Greek. They are the only mammals capable of true powered flight. Bats have the same bones in their forelimbs as all mammals including humans. However, their hands and fingers are elongated to provide support to the wing membrane (made up of skin) which stretches between the fingers and attach to the side of the bat all the way to its lower leg. The hindlimbs of bats are also unique in that the hip joint is rotated 90° so that legs project sideways and the knee faces backwards! One of the most amazing features of most bats is their ability to echolocate. That is, they listen to echoes from sounds that they emit while flying to orientate themselves as well as to locate their prey. Basically, they listen to the difference between what they 'say' and what they 'hear' to gather information about their surrounds. The echolocation calls that most bats emit are ultrasonic, i.e. above the range of human hearing. Another amazing feature about bats is that for their size, they display extraordinary longevity. Recently scientists in Siberia found a bat, Myotis brandtii which was at least 40 years old!
Bats at Montagu Guano Cave
Information supplied by Lizelle Odendaal.
There are 116 species that are known to occur in southern Africa. Montagu Guano Cave is home to 4 (possibly 5) species. The Cave and the surrounding area is extremely important for the long term survival of these bats because the Cave serves as a maternity roost. Every summer, mothers return to this cave to give birth to and care for their young. The two most common bats at the Cave is the Natal long-fingered bat, Miniopterus natalensis, and Temminck's hairy bat, Myotis tricolor. These bats often roost together in other areas of the Western and Eastern Cape but usually form separate clusters within the roost. Both species are known to migrate between winter hibernacula and summer maternity roosts. Miniopterus is brownish-black although colour can be very variable in other parts of the country. They have an average mass of about 11g and a total body length of about 110 mm. Their dark, almost black wings are long and pointed which allows them to be extremely fast fliers and they usually fly quite high. One unique feature of these bats is the fact that when roosting, the tapered tips of their wings are folded back, thus they are also known as bent- wing bats. They use echolocation to detect and capture their insect prey. These bats have special requirements for their roosts, especially the maternity roosts in which females give birth. Therefore, even though they are found in many parts of the country, their survival depends on the availability of warm, moist roosts, like the Montagu Guano Cave.
Myotis tricolor has reddish fur with dark brown wing membranes. They have an average mass of 12g. Their wings are short, broad and pointed which allows them to have manoeuvrable flight close to vegetation where they are able to catch their insect prey. This species is also dependent on the availability of suitable maternity roosts.
The third species found at Montagu Guano Cave is Geoffroy's horshoe bat, Rhinolophus clivosus. They are called horseshoe bats because of folds of skin on their faces which are shaped like a horseshoe. They also have an average mass of 16g and are greyish or reddish brown in colour. Their ears are long and pointed, unlike Myotis and Miniopterus and they also feed on insects but their diet usually consists mainly of beetles. Another horseshoe bat species- the endemic Cape horseshoe bat, Rhinolophus capensis, may also occur at the Guano Cave This bat is smaller than Geoffroy's horseshoe bat (weighs approximately 10-12 g). There are indeed museum records of this species from Montagu, so it is likely that they still occur there, but possibly in much lower numbers compared to Miniopterus and Myotis.
The final bat that occurs at the Guano cave is the widely distributed Egyptian free-tailed bat, Tadarida aegyptiaca. This bat is medium sized and weighs about 15g. They have very dark fur but the wings are slightly brown. Unlike all the other bats at the Guano cave, the Egyptian free tailed bat prefers to roost in rock crevices or under exfoliating rocks. The cliffs which house the Guano Cave are therefore perfect roosting sites for this species. This species has long narrow wings and they usually fly very high above vegetation.
In conclusion, Montagu Guano Cave is certainly a very important roost for a number of species. This is highlighted by the fact that the Cave is used as a maternity roost, and therefore, the Cave should be protected and bats should be disturbed as little as possible. Also, because all of the species found at the Guano Cave prey on insects, they freely perform a valuable service for the surrounding area...and that its to eat as much insects as possible which means that there are less insects around at night to bother us!