The Rakali – (Eastern Water Rat) Rodents of the World Rodents of the World Australian rodents Australian rodents Evolution Evolution Rakali breeding Rakali breeding The Rakali pelt The Rakali pelt The Rakali diet The Rakali diet Habitats Habitats Rakali research – Swan Bay Rakali research – Swan Bay Michelle Smith

Rodents of the World Order Rodentia Order Rodentia Squirrel, beaver, porcupine, guinea pig, capybara, mice, rat Squirrel, beaver, porcupine, guinea pig, capybara, mice, rat Large, gnawing incisors Large, gnawing incisors Strong jaw muscles Strong jaw muscles Varied diet, including tough woody plant material

Australian Rodents 55% marsupials, 22% rodents, 22% bats, 1% monotremes 55% marsupials, 22% rodents, 22% bats, 1% monotremes 61 rodent species – 6 introduced 61 rodent species – 6 introduced 4 self-introduced, including black and brown rats, and house mouse

Evolution of the Rakali 14 genera of native rodents 14 genera of native rodents Most are “Old Endemics” - including Rakali Most are “Old Endemics” - including Rakali Rakali in Hydromyinae subfamily – 9 in New Guinea, 2 in Australia Rakali in Hydromyinae subfamily – 9 in New Guinea, 2 in Australia False Water Rat in coastal Nth Qld False Water Rat in coastal Nth Qld Rakali widespread, although patchy Rakali widespread, although patchy Aquatic niche – fur and feet adapted Aquatic niche – fur and feet adapted

Rakali Breeding Females breed at approx. 5 months age for 3 seasons Females breed at approx. 5 months age for 3 seasons Spring / summer breeding in Victoria Spring / summer breeding in Victoria 1 – 7 in litter, average of 4 1 – 7 in litter, average of 4 Blind, short-furred and grey/black at birth, with white tail tip Blind, short-furred and grey/black at birth, with white tail tip Eyes open at 14 days, and eat some solids at 3 weeks Eyes open at 14 days, and eat some solids at 3 weeks Weaned at 4 weeks Weaned at 4 weeks

The Rakali Pelt Thermal balance and buoyancy Thermal balance and buoyancy Colours vary according to geography Colours vary according to geography All have white tail tip All have white tail tip Black and orange individuals more aggressive Black and orange individuals more aggressive Hunted until 1938 Hunted until 1938

The Rakali Diet Carnivorous Carnivorous 2 molars per row instead of 3 – required for crushing hard-shelled prey items 2 molars per row instead of 3 – required for crushing hard-shelled prey items Most prey taken in water Most prey taken in water Fish, molluscs, birds, amphibians, insects, Fish, molluscs, birds, amphibians, insects, lizards, eggs, spiders, yabbies, turtles, crabs, snails, carrion, small mammals, crayfish, crustaceans, rubbish Climb trees! Climb trees!

Capturing and Consuming Prey Eyes opened underwater, ears closed Eyes opened underwater, ears closed Prey captured and carried in mouth Prey captured and carried in mouth Prey taken to suitable feeding tables Prey taken to suitable feeding tables Leave behind evidence including crab and mollusc shells, yabbie remains, fish scales, bones, feathers etc. Leave behind evidence including crab and mollusc shells, yabbie remains, fish scales, bones, feathers etc.

Rakali Habitat Mainly considered freshwater animal Mainly considered freshwater animal Inland rivers and irrigation channels Inland rivers and irrigation channels Permanent water bodies Permanent water bodies Little research or knowledge of coastal habitats Little research or knowledge of coastal habitats

Rakali Habitats - General Dense vegetation cover or rocks Dense vegetation cover or rocks Low banks preferable to flat water edge Low banks preferable to flat water edge Stable and friable soil Stable and friable soil Semi-submerged hollow logs Semi-submerged hollow logs Round burrow entrance in bank Round burrow entrance in bank

Rakali in Coastal Zones In Victoria, Rakali have been located at: In Victoria, Rakali have been located at: Melbourne (Williamstown, Port Melb, St Kilda, Elwood, Brighton, Black Rock) Melbourne (Williamstown, Port Melb, St Kilda, Elwood, Brighton, Black Rock) Mornington Peninsula (Sorrento) Mornington Peninsula (Sorrento) Bellarine Peninsula (Clifton Springs, Swan Bay – Queenscliff) Bellarine Peninsula (Clifton Springs, Swan Bay – Queenscliff) Westernport Bay (French and Phillip islands) Westernport Bay (French and Phillip islands) Wilsons Promontory (Corner Inlet) Wilsons Promontory (Corner Inlet)

Rakali Research at Swan Bay Sandy beaches, mudflats, saltmarsh Sandy beaches, mudflats, saltmarsh Capture – Mark – Recapture Capture – Mark – Recapture Individually ear-tagged Individually ear-tagged Animals weighed, measured Animals weighed, measured Injuries assessed Injuries assessed Released at point of capture Released at point of capture

Rakali at Swan Bay Feeding tables investigated Feeding tables investigated Prey items identified Prey items identified Stomach, intestinal and faecal contents examined Stomach, intestinal and faecal contents examined Habitat variables defined and analysed Habitat variables defined and analysed Bank characteristics Bank characteristics Distance Distance Prey abundance Prey abundance Plant species Plant species Soils Soils Veg density Veg density Disturbance Disturbance Rocks and logs Rocks and logs

Rakali at Swan Bay – Populations 156 males and 94 females (20 hectares) 156 males and 94 females (20 hectares) Sex ratio of 1.5 males: 1 female Sex ratio of 1.5 males: 1 female 72% were adults 72% were adults 33% males with injuries 33% males with injuries Male weight – 776g (375g - 975g) Male weight – 776g (375g - 975g) Female weight – 636g (330g – 840g) Female weight – 636g (330g – 840g)

Rakali at Swan Bay - Diet 50% Rock Crab 50% Rock Crab 20% Mottled Shore Crab 20% Mottled Shore Crab 20% Surf Crab 20% Surf Crab Other components included: Other components included: Smooth Seaweed Crab Smooth Seaweed Crab Pilchard Pilchard Silver Gull Silver Gull Prickly Toadfish Prickly Toadfish Smooth Pebble Crab Smooth Pebble Crab Shore Crab Shore Crab Bridled Leatherjacket Bridled Leatherjacket Pheasant Shell Pheasant Shell No luck with gut analysis No luck with gut analysis

Rakali at Swan Bay - Habitat Coast Saltbush - (Atriplex cinerea) Saltmarsh vegetation: Shrubby Glasswort, Beaded Glasswort, Austral Seablite, Coast Saltbush, Marsh Saltbush, Southern Sea-heath,

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