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Full-Text Articles in Animal Sciences
Mortality Of White-Tailed Deer In Northeastern Minnesota, Michael E. Nelson, L. David Mech
Mortality Of White-Tailed Deer In Northeastern Minnesota, Michael E. Nelson, L. David Mech
USGS Northern Prairie Wildlife Research Center
Abstract: Two hundred nine white-tailed deer (Odocoileus virginianus) were radiotracked in the central Superior National Forest, Minnesota, from 1973 through winter 1983-84; 85 deaths were recorded. Annual survival was 0.31 for fawns (<1.0 years old), 0.80 for yearling (1.0-2.0 years old) females, 0.41 for yearling males, 0.79 for adult (≥2.0 years old) females, and 0.47 for adult males. Monthly survival rates were high from May through December (0.94-1.00), except for yearling (0.60) and adult (0.69) bucks during the November hunting season. Most mortality occurred from January through April when gray wolf (Canis lupus) predation was an important mortality source for all cohorts. Yearlings males were most vulnerable to hunting and adult males to wolf predation.
Relationship Between Snow Depth And Gray Wolf Predation On White-Tailed Deer, Michael E. Nelson, L. David Mech
Relationship Between Snow Depth And Gray Wolf Predation On White-Tailed Deer, Michael E. Nelson, L. David Mech
USGS Northern Prairie Wildlife Research Center
Abstract: Survival of 203 yearling and adult white-tailed deer (Odocoileus virginianus) was monitored for 23,441 deer days from January through April 1975-85 in northeastern Minnesota. Gray wolf (Canis lupus)predation was the primary mortality cause, and from year to year during this period, the mean predation rate ranged from 0.00 to 0.29. The sum of weekly snow depths/month explained 51% of the variation in annual wolf predation rate, with the highest predation during the deepest snow.
Variations In Radial Maze Performance Under Different Levels Of Food And Water Deprivation, Robert H.I. Dale, William A. Roberts
Variations In Radial Maze Performance Under Different Levels Of Food And Water Deprivation, Robert H.I. Dale, William A. Roberts
Scholarship and Professional Work - LAS
Four groups of rats were tested on an eight-arm radial maze under a free-choice procedure. The subjects were maintained at either 80% or 100% of their preexperimental free-feeding weights through restricted access to either food or water. Water-deprived subjects received water in the maze; food-deprived subjects received food. Water-deprived subjects learned the task faster than food-deprived subjects. The four groups developed different response patterns. These were measured by the mean transition size, the average angular distance (in 45° units) between consecutively chosen arms. Rats foraging for food and water developed different search strategies, with water-deprived subjects exhibiting lower mean transition …
Interactions Between Response Stereotypy And Memory Strategies On The Eight-Arm Radial Maze, Robert H.I. Dale, Nancy K. Innis
Interactions Between Response Stereotypy And Memory Strategies On The Eight-Arm Radial Maze, Robert H.I. Dale, Nancy K. Innis
Scholarship and Professional Work - LAS
Three groups of water-deprived rats collected water from the ends of the 8 arms of an 8-arm radial maze. Sighted subjects, and subjects blinded either with or without pre-enucleation experience on the radial maze, all retrieved the water efficiently. Most of the subjects exhibited the same response stereotypy, regularly choosing 8 adjacent arms of the maze, then stopping in the center of the maze. The strategies underlying this performance were analyzed by interrupting trials and rotating the maze 180° after the subject had made 3 choices. Sighted subjects depended on extramaze stimuli, naive-blind subjects depended on intramaze stimuli and experienced-blind …
Spatial And Temporal Response Patterns On The Eight-Arm Radial Maze, Robert H.I. Dale
Spatial And Temporal Response Patterns On The Eight-Arm Radial Maze, Robert H.I. Dale
Scholarship and Professional Work - LAS
Six maze-experienced hooded rats were timed during five trials on which they collected water from all arms of an eight-arm radial maze, then made five more choices. All subjects frequently exhibited a “task-completion pause:” The subjects rarely spent more than 1 sec in the center of the maze between choices until they had entered all eight arms, then stopped in the center of the maze. In contrast, the time spent in each arm gradually increased until all of the water had been obtained, then decreased slightly. Four subjects began every trial by choosing eight consecutive adjacent arms. The task-completion pause …
The Hold-Release Mechanism In The Family Crotalidae, Ronald K. Easter
The Hold-Release Mechanism In The Family Crotalidae, Ronald K. Easter
Masters Theses
Strike/release vs. strike/hold feeding behavior was observed for 5 Crotalus atrox and 5 Agkistrodon piscivorous. Two sizes of warm blooded prey were offered to the rattlesnakes on alternate weeks. Cottonmouths were offered, alternately, fish or mice of equal size. Although data varied among individual subjects, cottonmouths offered fish demonstrated the strike/hold behavior significantly more often than the strike/release behavior; cottonmouths offered mice struck and released significantly more often than they struck and held. It is concluded that the strike/hold strategy in sreponse to fish is adventageous because the danger of holding such prey is minimal and the release of …