Why are nutritional studies often limited in value? (3 main reasons)
- Tell us WHAT was eaten, but not how much or why
- Provide limited information. For example, animals will change their food habits seasonally
- No synthesization? (Ask Doug)
State three functions water provides in an animal’s body (can you state all 6?).
- Lubricating skeletal joints
- Transport sound and light within the ear and eye
- 99% of molecules in body are water
- Essential for the solvent of salts, ions, and gases,
- temperature control a.k.a thermoregulation (evaporation)
- Critical in metabolic reactions.
Why does the elimination of ammonia vary between birds and mammals? Why have birds evolved this method?
Mammals:
- Combined with CO2 and converted into urea. Urea is easily dissolved in water, making urine, which is expelled. This method is wasteful of water and adds weight.
Birds:
- Need to stay light. Instead, they convert ammonia to uric acid, which is excreted as a white paste or dry white powder.
How is water lost from an individual (5 methods)?
- Percutaneous (slow loss of water through the skin).
- Expired air (e.g. panting, gular flutter, respiration).
- Body surface (sweat & thermoregulation).
- Excretions (urine & feces).
- Milk, eggs, and parturition.
How is water gained by the body (4 sources)?
- Air or soil/skin interface
- Metabolic or oxidative water. (obtained from the oxidation of foods/fat)
- Preformed water: water found in food as water molecules
- Free water: liquid water available in the environment
What are the % dietary requirements for protein for ungulates? Carnivores?
- Herbivores: 5.5 – 12% of their diet.
- Carnivores: 19-25% of their diet.
What factors influence the amount of protein an individual needs?
Stage of life in terms of reproduction/growth:
- Molting, feathers, horn and antler development increase >85%
- Lactation, 12-15% over maintenance
- Young hatchling (85-165%), Precocial (230%)
What factors influence the amount of protein available in the environment and how do herbivores compensate?
Protein availability changes with season. Most in Spring, least in Winter in grasses and shrubs.
Herbivores can get protein during the growing season, but not in winter.
So, herbivores will feed selectively on sources of high protein content:
- New tissue
- Leaves instead of stems
- Terminal tips instead of older branches
What are ‘macro-minerals? Micro-minerals?
Macro-minerals are needed in large amounts:
- calcium, phosphorous, chloride, magnesium, sodium, potassium, sulfur.
Micro-minerals needed in small amounts:
- iron, zinc, manganese, copper, iodine, fluoride, etc
What are the following minerals needed for in the body:
a. Calcium & phosphorous?
b. Magnesium?
c. Sodium, potassium, & chloride?
a. Ca and P needed for skeletal growth and maintenance, horns and antlers, egg shell production, milk production.
b. Mg is major constituent of bone and numerous enzyme systems
c. Sodium, potassium, and chloride; biochemical activities
Why:
a. Do seed eaters consume bone or antler?
b. Does eating lush vegetation leads to death in some herbivores?
c. Do moose eat aquatic vegetation?
d. Do herbivores use mineral licks?
a. To supplement calcium intake - seeds are deficient in calcium
b. Following a period of poor nutrition, lush vegetation reduces animal’s ability to absorb magnesium, resulting in convulsions and death
c. To supplement sodium intake. Aquatic veg has more sodium content
d. To supplement sodium intake, as sodium is deficient in plants eaten by herbivores
What are the fat-soluble vitamins and the water-soluble vitamins?
DEAK, are fat soluble - can be stored for later use
BC are water soluble and cannot be stored
What are the causes of rickets & scurvy?
Rickets:
- Vit D needed to absorb calcium. Deficiencies result in softening of bones and deformity.
Scurvy:
- Scurvy is a disease resulting from a deficiency of vitamin C which is required for the synthesis of collagen in humans
Which vitamins, in general, are usually deficient in natural habitats for wildlife?
- ## Vitamin A seasonally, because synthesized from carotene which is mostly in new plant growth
(ASK DOUG)
What is the primary purpose of carbohydrates to wildlife?
CHO broken down by animals to produce GLUCOSE– source of energy.
What function do lipids perform in the body?
Animals use lipids for:
- source of energy,
- energy storage,
- constituent of cell membranes.
Why is the food eaten by carnivores better quality than food eaten by herbivores?
- Plant cell walls are composed off cellulose which is largely indigestible for most animals.
- Animal tissue is almost 100% digestible (except hair, feathers, bone).
- Animal cells are more-likely to contain all the necessary nutrients for animal growth and maintenance than are plant cells.
Explain how animals (carnivores and herbivores) can be selective in the food they eat to maximize the benefit to their body?
Different tissues contain different vitamins, minerals fats. Thus carnivores selective: fats and organs > muscle tissue.
Herbivores:
- Grazers select leaves over stems.
- Browser select leaves and new twig growth.
- Consume other food items to supplement V&M
Why is the concept of cover difficult to define and identify? (4 reasons)
- Animals use cover for a wide variety of purposes
- Our descriptive terms of cover are confusing.
- Animals use much more cover than the minimum required for survival.
- Poor understanding of the different forms cover may assume
Describe the three components (stages) of the act of predation. What are the key features of escape cover needed for each stage?
- Random Search. Escape cover:
- cover as concealment, breaks up shape, visually dense - Pursuit Phase: (stalk and chase)
- complex structure and multiple paths. Mechanical density and complexity probably more important than concealment. - Refuge
- prey eludes and needs refuge: burrows, cavities, trees, steep cliffs, etc
From an ungulates perception, what type of cover provides the best ‘shelter’ and why?
Stands of dense, mature timber exhibit the narrowest thermal range, warmest average temperatures, lowest wind flow, and least hazardous snow conditions.
- Deer’s radiant and convective heat losses are minimized under thick conifers.
Why is interspersion of cover types a good feature for some species?
The interspersion of the various cover types and food that will provide the best habitat for an individual. Can be supplied within one habitat or in adjacent habitats.
Young forest - good food
Older stages - less food, more cover
intermediate - snow interception and thermal
Which species of ungulate ‘yard up’ and what does this mean? Based on bioenergetics, why do they yard up?
Moose, caribou, and white-tailed deer yard-up.
May be due to thermal needs - yarding up preserves heat. May be linked to winter food supply.
Trampling down and creating trails between feeding sites and sleeping sites. Preserving energy to food ratio.
Why did the provision of reproductive cover for wood ducks by biologist fail?
Usually, cavity nests are covered by vegetation.
Artificial nests didn’t have cover, so brood parasitism occurred. Nests are oversaturated with eggs and mothers abandon nests.
