Tag Archives: animal adaptations

But I eat lots of carrots!

Image of Quentin the Quoll
Quentin the Quoll talks about nocturnal animals

Did your mum ever tell you to eat lots of carrots because they would help you to see better in the dark? Whilst carrots and other orange and yellow fruits and vegetables will help to prevent certain eye ailments, to see really well at night you actually need special eyes.

Like other nocturnal animals, Quentin the Quoll was able to find food and evade prey even on the darkest of nights. In fact before the disappearance of dinosaurs, most land mammals were nocturnal since dinosaurs were their main predators. Today there is more of a balance but animals such as owls, possums, gliders, many frogs, bats, wombats, koalas, phascogales, many wallabies and geckoes are but a few of the Australian animals that still use the cover of night to survive.

So how do nocturnal animals see so well in the dark?                  Eye of Tawny Frogmouth chick

Of course there are variations in eye features across different animals but scientists have discovered some common characteristics. The most obvious one is eye and pupil size. Some animals like owls, frogs and geckos have eyes that take up a much larger percentage of their skull compared with diurnal (daytime active) animals. Their large eyes and pupils give them large lenses and therefore bigger retinas so that they maximise the amount of ambient light they collect. However, larger eyes means reduced space for each eye to move within the skull, so these nocturnal animals have developed the ability to rotate their necks way past their shoulders to compensate.

Sugar glider

As well as eye size, nocturnal animals have retinas which are filled with rods, the eye cells which detect low light levels. They often have few or no cones which are the eye cells responsible for detecting bright light and colour. Again this helps to maximise the amount of light being collected but as a result, nocturnal animals are thought to have little colour vision and things probably look blurry.

Consequently, nocturnal animals also rely on their senses of smell and hearing.

One final common characteristic in nocturnal eyes is a thick, reflective membrane directly beneath the retina. This membrane, called the tapetum lucidum, collects and resends light back to the retina a second time, giving the rods another chance to absorb the image information. This also explains why some nocturnal animals’ eyes seem to glow in the dark when a light is shined on them. Cats too have nocturnal glow in the dark eyes, which explains why they are such a threat to wildlife at night.

Image of the Graceful Treefrog
Graceful Treefrog

The purpose of this blog is two fold. Firstly, it is hoped that this information will support the delivery of the Australian Curriculum: Science. It is most directly linked to the Year 5 Science Understandings (Biological sciences — Living things have structural features and adaptations that help them to survive in their environment) and Science as a Human Endeavour (Use and influence — scientific knowledge is used to inform personal and community decisions). However, it is also a real life example of the Year 5 Science Understandings (Physical sciences — Light from a source forms shadows and can be absorbed, reflected and refracted) and will provide teacher background information for Science Understandings in Year 1(Earth and space sciences — Observable changes occur in the sky and landscape) and Year 3 (Biological sciences — Living things can be grouped on the basis of observable features…)

The second purpose is to make you aware of a new Queensland Museum digital resource called Squawks in the night. It is a slide show designed specifically for Early Years learners, with simple text that relates directly to the photos and a few animal calls. The resource is located on the Queensland Museum website via the following link.

http://southbank.qm.qld.gov.au/Learning+Resources/~/media/Documents/Learning%20resources/QM/Resources/Kids%20collection/squawks-in-the-night.ppt

We welcome any feedback or requests for particular topic discussions/resources. Please contact QM teachers 07 3842 9835.

Prehistoric Beasties!

Federica Turco is a post-doctoral research fellow working at Queensland Museum. She and research associate, Geoff Monteith, are investigating some amazing beetles living in dark caves near Rockhampton. These beetles have been around since the Pleistocene epoch (approx 2.6 million – 12,000 years before the present) and possibly even the Late Pliocene (3.6 million years ago).

They belong to the genus Mystropomus (Order: Coleoptera; Family: Carabidae) and the whole family is composed of ground-dwelling predatory beetles.

Adult Mystropomus

These ancient creatures crawl over cave floors, lying in wait for their invertebrate prey. Even the larvae are predatory using a weird structure at the end of their abdomen to snare their prey. First they dig out a burrow in the soil in a sheltered place.

Larva in burrow

Then they close over the hole with their enlarged abdomen covered with sensitive setae (bristles). As soon as any prey walks over this, the setae trigger a quick response from the larva, which backflips to grab the prey with its huge mandibles (jaws). So these creatures have amazing structural and behavioural adaptations to help them catch their food.

Larva ready to attack

Beetles such as these once inhabited the rainforest regions of Queensland but with the Great Drying some moved to higher rainforest regions and some found shelter in cave environments. Fede and Geoff are collaborating with Wendy Moore (University of Arizona) and Andrea Di Giulio (University “Roma Tre”), who are specialists on this sub-family of Carabidae (Paussinae). There appears to be two species, one that is found from Sydney up the coast to Mackay, and another species that inhabits the wet tropics from Bowen to Cooktown. The cave populations may belong to a third new species but work is still in progress.

You can learn more about animal adaptations by watching some animal adaptation videos that come with a student worksheet linked to the Australian Science Curriculum. To learn more about some of the effects of the Great Drying and how this affected the evolution and distribution of some Australian species, you can view the online learning resource Dinosaurs, Climate Change and Biodiversity.

Visit Queensland Museum’s website on Beetles to find out more about these amazing creatures.