Common cattle grub vs Common Water Rat

Hypoderma lineatum compared with Hydromys chrysogaster

Key Differences

• Common cattle grub is Extinct while Common Water Rat is Least Concern.

Taxonomic Classification

Rank	Common cattle grub	Common Water Rat
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Arthropoda (Arthropods)	Chordata (Chordates)
Class	Insecta (Insects)	Mammalia (Mammals)
Order	Diptera (Diptera)	Rodentia (Rodents)
Family	Oestridae	Muridae (Mice & Rats)
Genus	Hypoderma	Hydromys
Species	Hypoderma lineatum	Hydromys chrysogaster

Evolutionary Relationship

Common cattle grub and Common Water Rat share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

Common cattle grub

EX — Extinct

Common Water Rat

LC — Least Concern

Physical Characteristics

Attribute	Common cattle grub	Common Water Rat
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common cattle grub

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Japan, Norway, Sweden, and United States.

Common Water Rat

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Common cattle grub

<em>Hypoderma lineatum</em>, commonly known as the common cattle grub, is a parasitic fly species with documented occurrences in Japan, Norway, Sweden, and the United States. It typically inhabited terrestrial and freshwater environments, often associated with cattle and other large ungulates on which its larvae develop as subcutaneous parasites. The species is classified as Extinct on the IUCN Red List, indicating that it is no longer known to exist in the wild. Common cattle grub belongs to the genus <em>Hypoderma</em> within the family Oestridae. Adult flies do not feed and are short-lived, while larvae burrow under the skin of host animals, causing a condition known as hypodermosis or warble fly infestation. The decline and extinction of this species has been linked to widespread and highly effective veterinary treatment programs targeting warble fly larvae in cattle, which drastically reduced host populations and ultimately eliminated the species. Biological traits such as average lifespan, body length, and mass of this species remain poorly documented in the scientific literature.

Common Water Rat

<em>Hydromys chrysogaster</em>, commonly known as the common water rat or rakali, is a semi-aquatic rodent in the family Muridae, native to Australia and New Guinea. It is classified as Least Concern by the IUCN, reflecting its relatively stable population across a broad range of freshwater and estuarine habitats on the Australian continent and associated islands. The species typically inhabits the banks of rivers, lakes, wetlands, and estuaries, where it constructs burrows in streambanks. It is highly adapted for an aquatic lifestyle, with partially webbed hind feet, a flattened head, and a dense waterproof coat. <em>Hydromys chrysogaster</em> is a carnivore, typically feeding on fish, crustaceans, mussels, frogs, and aquatic invertebrates, which it often carries to elevated feeding platforms to consume. The species is nocturnal and crepuscular, most active during early morning and evening hours near the water's edge. Biological traits including average lifespan, body length, and weight remain poorly documented in standardized databases, though adults are generally robust for a rodent, reportedly reaching body lengths of 20–35 cm excluding the tail. Geographic range details for this particular record remain incompletely documented in available data sources. Ecologically, the common water rat is an important apex predator in small-scale freshwater food webs and serves as an indicator species for wetland health in Australian riparian systems.