Common Yabby

Yabbies are on average 10–20 cm (4–8 in) in length, but have been shown to grow to lengths of up to 30 cm (12 in).

The common yabby has a smooth shell with one pair of post-orbital ridges. It does not have a spine on the shoulders behind the cervical groove (region that separates head from thorax). Females have a reduced growth rate after maturity which usually means that they are smaller in size compared to their male counterparts

Colour is highly variable and depends on water clarity and habitat; yabbies can range from black, blue-black, or dark brown in clear waters to light brown, green-brown, or beige in turbid waters. Yabbies specifically bred to be a vibrant blue colour are now popular in the aquarium trade in Australia.

Yabbies, are largely nocturnal, and mostly feed during periods of low light like at dusk or dawn. Due to the low-light levels of many of the habitats in which they live in, yabbies often utilize nonvisual sensory systems to detect and capture live prey. Some of these sensory systems include chemoreception and tactile senses.

Due to an ability to extract organic nutrients efficiently from many different food sources, yabbies often use a non-selective approach to obtaining prey as juveniles, being carnivores, herbivores, and detritivores.

Using coordinated movement of their legs and mouths, yabbies forage for many types of food efficiently. Among many other prey, Zooplankton is one of the common yabby’s most common sources of food. Yabbies are known to be able to distinguish between live and dead zooplankton and also change their feeding behaviour depending on their size.

Yabbies are largely active at night, living in underwater burrows and in turbid waters as a protective measure from predators. In addition, the turbid environments in which many yabbies live severely reduce the amount of light that reaches the bottom and consequently reduces the value of visual sensory systems. As a result, they often utilize nonvisual cues to navigate their environment while scavenging for food like plants and other arthropods. Tactile clues are often utilized by yabbies through their antennas, allowing them to create a spatial configuration of the world around them during the night and in visually clouded environments while maintaining the ability to obtain food and retreat to their shelter when threatened.

Clutch size, brood size, development rate, and other reproductive factors of yabbies vary significantly depending on both genetic and non-genetic factors. Studies have shown that some phenotypic factors, such as female body weight, were positively correlated with clutch and brood size although brood sizes were often lower than clutch sizes. In addition, environmental factors like temperature were negatively correlated with developmental time which ranged from 33.4 to 42.2 days, indicating a faster rate of development at higher temperatures within a certain range. However, these results also showed large variability even within the same species Cherax Destructor.

Although they are not considered an endangered species, they are considered to be vulnerable by the IUCN. Here, vulnerable refers to how this species may face a high rate of extinction in the wild. This is because their habitat is under constant threat from agricultural chemicals like fertilizers and pesticides. Also, degradation of native vegetation also makes their habitat more vulnerable.

Although this organisms habitat is under threat they are still considered a very adaptive species and are involved in very rapid breeding