Life As a Hunter-Round 1

Name: ______Date: ______

Life as a Hunter-Round 1

Life is challenging for a female lion in Etosha National Park. If a female’s body size is approximately 130kg, she must consume 13,500 kcal per day to survive and succeed in the environment. There are ample prey species available, but just living and breathing costs a significant amount of energy per day. This means that regardless of her hunting success, she will utilize energy for her resting metabolic rate. All animals have a reserve of energy stored as large molecules in their cells that they can use for activities throughout the day. Female lions have approximately 15,000 kcal stored, therefore, when hunting, they cannot expend/use more than 15,000 kcal per day hunting.

Listed below are four prey species lions will hunt and the energy costs and gains to hunting each type of food source.

Total energy cost to hunt & Total energy available per Mass of prey item kill (kcal) kill (kcal Meerkat 0.77 kg -3,000 +5,000 Warthog 60 kg -5,000 +12,000 Wildebeest 265 kg -10,000 +25,000 Zebra 310 kg -49,000 +170,000

Scenario: You are tracking a female lion. Using the table below, determine how many of each prey species she would need to successfully hunt and eat to gain the amount of energy she needs per day (13,500 kcal). Remember, an individual lion cannot expend more than 15,000 kcal per day hunting. Use the following calculations to determine the net energy gained in kilocalories for the table below.

• Total energy cost to hunt prey = (number of prey hunted x energy cost per prey)

• Net energy gained = (number of prey hunted x total energy available) - total energy cost to hunt prey

I’ve completed the Meerkat portion for you. Below is an explanation on how I filled in each portion of the table. ✓ I chose 5 as the number of meerkats to consume, due to the fact that a female lion can’t expend/use more than 15,000 kcal per day. ✓ The -3000 represents the amount of kcal needed to hunt and kill each meerkat. ✓ The -15,000 represents the total amount of energy needed to hunt and kill all 5 meerkats. ✓ The 5,000 represents the total amount of energy gained from each meerkat. ✓ This is how calculate the Net Energy Gained, 1. I multiplied the total energy gained from each meerkat (5,000) by the number of meerkats consumed (5), this equals 25,000 kcal of total energy gained. 2. Next, I multiplied the energy needed to hunt and kill each meerkat (-3000) by the total number of meerkats killed (5), this equals -15,000 kcal. 3. Finally, I simply subtracted the energy used to hunt (-15,000) from the energy gained (25,000) giving me a net energy gain of 10,000 kcal. 4. The reason it is NOT worthwhile to hunt on your own is due to the fact that less than 13,500 kcal per day.

Total energy cost Total energy Energy cost to hunt prey Is this species Number of prey available from per prey (must not expend Net energy gained worthwhile to hunted and each of these (kcal) (-) more than 15,000 (kcal) hunt on your consumed prey (kcal) kcal per day) (-) own? (+)

• 25,000 gained Meerkat 5 -3000 -15,000 5,000 • -15,000 used No • Net kcal = 10,000

Warthog

Wildebeest

Zebra -

1. Lions rest about 90% of the time, allowing for only 1-3 hunting events per day. Which is a better way to use their energy: hunting small prey more often or large prey less frequently? Explain your reasoning.

2. What strategies must the lions use to capture a larger prey item?

3. Hunting can be dangerous for both predator and prey. What negative consequences might a lion encounter from hunting larger prey versus smaller prey?

Hunting Solo or in Groups? Now the same female is hunting a zebra with three other females. Using the Claim, Evidence and Reasoning format below, determine whether hunting solo or in groups is more effective. • Hint: Think about how the energy used to hunt each prey changes when 4, not only 1 lion hunts.

Claim: What do you know? Write a simple statement as to whether hunting solo or in groups is most effective.

Evidence: How do you know what you know?

Reasoning: How does your evidence support your claim?

Life as a Hunter-Round 2

1. How can an organism maximize their kcal intake and minimize their energy output?

Lions live in prides consisting of males, females and juvenile cubs. Depending on their sex, size, and age, lions have different kcal requirements per day.

• Males require 17,500 kcal/day Females require 13,500 kcal/day Juveniles require 11,500 kcal/day

The pride you are following consists of 1 male, 4 females, and 3 juveniles. Recall from the video, that females typically are the pride members that do the hunting.

2. Calculate how much energy your pride will need to sustain itself per day. Show your work!

3. What prey items should your pride attempt to catch to have enough energy for the day? You need to develop FOUR feeding scenarios in which you will be able to adequately supply the required energy for your pride, I’ve done the first one for you as an example. Show your calculations in the table below.

• Total energy cost to hunt prey = (number of prey hunted x energy cost per prey)

• Net energy gained = (number of prey hunted x total energy available) - total energy cost to hunt prey

I chose a zebra for the lions to hunt. Below is an explanation on how I filled in each portion of the table. ✓ I chose 1 as the number of zebras to consume, due to the fact that a female lion can’t expend/use more than 15,000 kcal per day. ✓ The -49,000 represents the amount of kcal needed to hunt and kill each zebra. ✓ The -49,000 represents the total amount of energy they used to hunt and kill 1 zebra. ✓ The -12,250 represents the total amount of energy used by each lion (-49,000 ÷ 4). “4 lions in the hunt” ✓ The 170,000 represents the total amount of energy gained from the 1 zebra. ✓ How I calculate the Net Energy Gained? If you forgot how, go back to the first page and look at the example.

4 Feeding Scenario

Total energy Number Energy Number Total energy cost to hunt Energy cost per Species of prey cost per of available from this Net energy for pride this number of hunter (-) hunted prey (-) hunters number of prey prey (-)

Zebra 1 -49,000 -49,000 -12,250 170,000 170,000 - 49,000 4 Net kcal = 121,000 kcal

4

4

4

4. Now that you have assembled the diets above, carefully review each and determine which combination of prey produces the optimal net gain of energy.

5. Explain how you decided which feeding scenario was optimal. Be sure to include specific evidence (data table #’s) in support of your choice of most efficient feeding scenario.

6. Beyond obtaining energy, what other benefits occur from living in a group?

7. Who are the lions’ main competitors?

8. How do lions feed and what types of behaviors do they utilize to obtain food?

9. How does this type of behavior impact their energy?

10. What benefit would they gain from hunting in this method?

11. How would living in a group affect competition with members of the same or other species?