Definitely one of the strangest looking animals I’ve seen that inhabits the Daintree rainforest has to be the Eastern Tube Nosed Bat. More often heard than seen with its whistling call that is quite loud and low pitched like a cross between a squeak and a little bell chime as it makes its way through the rainforest at night. Call frequency begins at 4800Hz and can ascend higher than 24000Hz. They are most vocal just after dark and before the dawn and I can promise that every long-time local of the Daintree region has heard them weather they realised it or not. There is a web site called WILDAMBIENCE that I recommend if you would like to hear their call. they have a great recording that was made somewhere in the Daintree Rainforest. I have been lucky enough to see a few of them over the years that I have lived here and they never cease to amaze and fascinate me. Once I was even in the right place at the right time to see a mother with her baby held tightly under her wing at Hutchinson’s Creek in Cow Bay.
To look at they can be considered the stuff of nightmares with their large protruding eyes and cryptic colours that closely resemble a dead leaf. A short blunt snout with the freakiest nostrils in the animal kingdom (Sorry proboscis monkey). But in reality they are totally harmless to humans and are in fact much smaller than they seem in pictures. (Although harmless it is not recommended that any type of bat be handled as some bats can carry diseases such as the Australian Bat Lyssavirus that can be transmitted from bites and scratches). They have a small to medium sized body for a bat with yellow spots on their brown wings and ears making them masters of camouflage. They have grey fur on the body with a black line running from the back of the neck to the rump, head and body length is only about 9.5 to 11 cm weighing from 42 to 56 g. They have a longish tail from 20 to 25 mm and short broad wings with a forearm length of 65 to 70mm that allow them great manoeuvrability and the ability to hover and then change direction an ability that is very rare in bats.
There are 14 species of tube nosed bat in the world, our one is the southernmost species and the only one found in Australia. Originally called the Queensland Tube Nosed Bat because they were thought to only be found in Queensland. This strange and enigmatic bat was first described to Science by Thomas Oldfield in 1904 from a male specimen that was collected at Cooktown in Far North Queensland. Its generic name Nyctimene, comes from the Greek word meaning “Night Moon” the name robinsoni was given to it by Thomas Oldfield to honour the naturalist Herbert C. Robinson who collected the first two specimens in Cooktown. Thomas Oldfield worked for the Natural History Museum in London he specialised in mammals and over his lifetime he described about 2000 new species and subspecies to science. It got a name change to the Eastern Tube Nosed Bat some time later by the Australian Museum in Sydney after its actual home range had been realised.
Tube nosed bats are considered “old world” bats and belong to the megabat or Pteropodidae family which also includes flying foxes. This means they do not echolocate or use sonar to find their food as microbats do. But rather use basically the same senses that we use such as sight and smell. Their name comes from their tubular nostrils that protrude from their face by about 5 – 6mm and can be both closed off and move independently. They were once thought to act like snorkels for the bat so it can breathe while eating juicy rainforest fruits. But now it is generally thought the long tubular nostrils actually aid in finding food by its scent. Pollen is also eaten by this species making them very important as a pollinating vector of rainforest trees, particularly the cauliflorous trees whose flowers are on the tree trunks below the rainforest canopy. They also can carry quiet heavy fruits up to half their body weight back to their roosts or other preferred feeding sites. In so doing they disperse a lot of seeds. They are considered frugivorous or fruit eaters. A lot of their diet we now know from observation consists of firm fleshed fruits like the Blue Quandong contradicting the old views of juicy fruits that require snorkels. When eating fruits, they wrap their wings around the food and hold it against their chest, they extract the juice by biting rather than licking and chewing the fruit then squeezing it with their tongue against the roof of the mouth spitting out the pulp that can be found in neat little dry parcels on the ground called spats under the tree where they have been feeding. They have nostrils able to move independently and lock onto the direction in which a scent plume is drifting from through the rainforest. Like how the forked tongue of a snake is used to find prey the side that picks up the most scent molecules is the direction the food is in. This is very useful locating fruit on a third dimensional plane. They are particularly fond of rainforest figs and most of the ones I’ve seen were on (Ficus racemosa) AKA the cluster fig tree. They can sometimes be found roosting with wings wrapped around their bodies fairly close to the ground. Sometimes between five and ten meters up on trees near to a fruiting tree or even on it. They are almost indistinguishable amongst dead leaves and often roost near some for added camouflage. At night they can be found by their bright red eye shine and whistling calls. They have been seen eating introduced fruits like guava, mangoes and soursop but seem to prefer their native diet. In captivity they are often considered fussy eaters and regular diet changes are needed and even then it is hard for them to gain and maintain a healthy body weight. Their diet consists of what is around in the habitat where they live. Heathland bats eat the nectar from banksia flowers and grass trees rainforest ones eat mostly fruit.
Unlike their cousins the flying foxes Eastern Tube Nosed bats tend to live a mostly solitary lifestyle only coming together in groups to feed and rarely venturing more than a kilometre or so from their roost sites to forage. Matting occurs from July to September and the gestation period lasts about 3.5 months. Birthing mostly seems to be from October to December and they have one baby or pup per year that is fed milk by its mother for a few months probably until the start of the next breeding cycle. Eastern Tube Nosed Bats are found on the East coast of Australia in a number of habitat types. They are the only members of the Nyctimene bat genus to be found on the Australian mainland. From rainforest to woodlands, heathlands and even open forest types but are most numerous in old growth rainforest. They range from just north of Lismore in NSW to Cape York at the top of Queensland and on islands in the Torres Strait. There is a separate subspecies that is found on the Solomon Islands and in New Guinea on islands and the mainland and into Indonesia.
Tube nosed bats are very important to the eco system as they both pollinate and disperse seeds of rainforest trees. In fact, they are the only small bat that can perform these duties in Australian tropical rainforests. One of the major threats to tube nosed bats is barbed wire fences as they don’t echolocate like microbats do they simply don’t see the danger and fly into the fencing wire and get caught on the barbs by the thin membranes of their wings. Each year six or more tube nosed bats are brought to the Tolga Bat Hospital that have met this fate. Unfortunately, most die due to the stress of the ordeal. Natural predators of this animal are mostly owls and snakes and they tend to stay at the roost sites on full moon nights to avoid being more easily seen by them. Also mites that are parasitic and are generally found underneath the wings these mites are common to all old world bats. Other threats include introduced animals like cats and crazy ants and of course the main threat to their and many more life forms existence is land clearing and habitat destruction. Luckily they are still being found in places where their habitat has been degraded. Although in much decreased numbers and they have even become a pest to some fruit orchards. Eastern Tube Nosed Bats are classified as vulnerable in the southern most parts of their distribution but rated of least concern in the northern parts of its home range.