Animals of dry lands Flashcards
Oryxes (2)
-Oryxes are extreme examples of large mammals that can survive indefinitely in hot deserts without drinking water
-They instead gain water from grazing
Rate of evaporative water loss and body size
As body size increases, evaporative water loss decreases.
Wildebeests (3)
-Wildebeests are dependent on water drinking, which can be difficult to do in the environment they live in
-To help them conserve water they seek out shade. The shade is cooler, meaning less evaporative water loss, and less water lost from metabolism, as cooler temps slow it down.
-Their foreleg muscles are the most efficient of any mammalian muscle, allowing them to still be very fast, but conserve more energy and water
Gazelles (2)
-Gazelles are another species that is able to live without drinking water, instead they get it from grazing.
-they dont seek shade, as being out in the open allows them to keep better watch for predators
Annual migration in the Serengeti (5)
-Driven by the seasonal change to water availability
-in the dry season, the water-drinking dependent wildebeest and zebras spend their time in the northwest as the southeaster plains receive almost no rain for months.
-At the start of the rainy season, they make their way to the southeastern plains where they will remine for the rest of the season
-Shortly after the rainy season, they make their way back to the northeast and the cycle repeats
- It is important to note, that only the water-drinking dependent animals follow this migration, where the non-drinking-dependent species are free to roam wherever they may choose
Human water use
Typically, as the town humans inhabit gets bigger, water use by individuals increases greatly
Wildebeest and Oryx water loss/gain (4)
-Similar sized wildebeest and Oryx went through 2 trials, one with the environment at 22c for 24 hours and 1 where the environment was 22c for 12 hours and 40c for 12 hours
-Wildebeests gained and lost significantly more water than Oryx
-wildebeests lost most of their water from urine and feces, whereas Oryx had an even split between urine/feces and evaporation
-Both species gained the vast majority as performed water (gained from food/drink) rather than metabolic water (water retention)
Grazing water uptake and time of day
Because of the high humidity and things like morning dew, the animals who gain their water from food often go out early in the morning to feed, as they are able to gain the most water that way. In other words, behavior will aid physiology in survival.
Seasons and nutritional content of plants (3)
-two species of grass were examined that are fed on by oryx and wildebeest
-It was found that protein content of the grass was significantly higher in the rainy season (dec-feb) than it was in the dry season,
-Protein content suffered a steep decline immediately when the rainy season ended, and a steep incline immediately when it started
The desert beetle (3)
-this kind of desert beetle collects water from desert fog in the Namib desert
-When the fog rolls in from the seam which often happens, the beetle goes to the top of a dune and sticks its ass in the air. As the fog condensates on its body, the water drips into its mouth
-it also has long legs to keep its body away from the hot sand
Waste and water concentration
In hotter environments, many animals increase the concentration of their urine and decrease the water content of their feces to conserve water.
Oryx body temperature (4)
-In the winter, the Orxy’s body temp remains pretty much the same throughout a 24 hour cycle, around 38c
-In the summer their metabolic rate increases during the hottest point of the day and decreases during the night.
-This is believed to be from a combination of stress due to heat, and a response to be able to escape predators
-During the night it allows them to conserve energy, which is then redirected to concentrating urine
