(628)-272-0788 info@etutorworld.com
Select Page

The Behavior of Animals

Grade 8 Science Worksheets

Response to Stimulus

All living organisms respond to the environment in which they live. This behavior can vary from actions such as –

  • Movement of a muscle
  • Secretion from a gland
  • Emotions and thoughts in higher animals.

The behavior is almost always in response to a stimulus received from the external environment. A bright light makes a human being blink. The same bright light makes a running deer freeze in their path. The sound of a predator elicits fear in a prey. We sweat or shiver if exposed to hot or cold temperatures. Such basic and spontaneous responses to external stimuli are native in every organism and are termed reflex actions. They take place without any thought process triggering them. They are the very basis of survival.

All animals have to cope with external disease and infection or any such threat to their existence and survival. Much of their behavior is induced by bacteria, viruses, parasites which infect their bodies. Animals are born with immune system passed on through their genes known as inborn immunity. This mechanism creates antibodies inside the organism to fight off disease and infection. Acquired immunity is the second kind that develops over time. The immune mechanism is yet another example of a response to external stimuli.

Schedule a Free session to clear worksheet doubts

No credit card required, no obligation to purchase.
Just schedule a FREE Sessions to meet a tutor and get help on any topic you want!

The Nervous System

Almost all multicellular organisms have some form of a nervous system, which varies from simple to very complex. It is a collection of special cells, known as neurons, which transmit signals between various parts of the body of the organism.

The simplest of nervous systems control responses to external stimuli such as light and touch, and in locomotion and other simple body functions.

Complex organisms have a brain which directs and controls these neurons. Neurons play different roles such as conveying information from sensory organs, managing motor activity, controlling internal organs and glands and enabling the learning process through past experiences.

The Endocrine System

All animals possess a endocrine system that secrete hormones that control various body functions. Hormones are chemical fluids carried in the bloodstream to help perform these various functions. The endocrine glands are much smaller than other organs but they perform very important functions such as growth, reproduction, sleep and wake times, hunger, thirst, digestion, moods, and emotions.

Natural Defenses

Animals exhibit many behaviors as a form of natural defense from predators. Some common ones are –

  1. Hiding
  2. Fleeing
  3. Showing aggression and fighting when isolated
  4. Vocalizing or communicating with others of their species
  5. Playing dead to fool their enemies
  6. Using protective colors to disappear in their environment
Learn more about Behavior of Animals and other important topics with 8th Grade Science Tutoring at eTutorWorld. Our expert science tutors break down the topics through interactive one-to-one sessions. We also offer the advantage of customized lesson plans, flexible schedules and convenience of learning from home.

eTutorWorld Understands Math Tutoring | Online Math Worksheets are Important Tools

Understanding graphs, charts, and opinion polls in a newspaper, for calculating house and car payments, and for choosing a long-distance telephone service are impossible without strong math skills …and the only way to develop strong math skills is by constant practice.

‘Practice makes a man perfect’ holds true for no other field better than for math. A middle or high school student must set aside a minimum of an hour for math every day. Other than textbooks, worksheets help you revise and understand concepts better.

Our expert tutors prepare online maths worksheets that are age and grade-appropriate. Grade-wise math worksheets for Elementary Math, Arithmetic, Pre-Algebra, Algebra, Geometry, Trigonometry, Statistics, Pre-Calculus and Calculus can be solved to improve math skills, to get ahead or to even catch up.

You may download these FREE online math worksheets in the PDF format, and then print and email us their solutions for a free evaluation and analysis by eTutorworld’smath expert tutors.

You may solve these worksheets by yourself or with your peers while studying together.

The Answer Key at the end of each worksheet allows for a self-evaluation.

Personalized Online Tutoring

eTutorWorld offers affordable one-on-one live tutoring over the web for Grades K-12, Test Prep help for Standardized tests like SCAT, CogAT, MAP, SSAT, SAT, ACT, ISEE and AP. You may schedule online tutoring lessons at your personal scheduled times, all with a Money-Back Guarantee. The first one-on-one online tutoring lesson is always FREE, no purchase obligation, no credit card required.

For answers/solutions to any question or to learn concepts, take a FREE CLASS.

No credit card required, no obligation to purchase.
Just book a free class to meet a tutor and get help on any topic you want!

Social Defense Mechanisms

Animals also exhibit social or group behavior such as flocking or moving in shoals or packs to ensure survival.

Some typical examples are –

  1. Birds stay together in flocks and fly in formation to reduce fatigue, enabling them to fly farther. They also tend to sick birds in their flock.
  2. Fish stay in shoals and the shoal swims together, known as a school. This protects them from predators as no member can be singled out for any attack.
  3. Wolves and lions hunt in packs to tackle a larger prey


Animal behavior is made up of a complex set of interacting mechanisms. They range from instant reflex actions, to “control and command” systems such as the nervous and endocrine systems, to social and group behaviors. When studied together, a complex and wondrous picture of the evolution of organisms emerges.

Check Point

  1. A spontaneous response to any external stimuli is known as a ______.
  2. Animals cope with disease and infection with ______ which produces ______.
  3. The nervous system has special cells called _____ to transmit signals between various parts of the body.
  4. Hormones are secreted by _____ in the endocrine system.
  5. Natural defenses are a form of protection from _____.

Answer Key

  1. Reflex action
  2. Immune system; antibodies
  3. Neurons
  4. Glands
  5. Predators

Schedule a Free session to clear worksheet doubts

No credit card required, no obligation to purchase.
Just schedule a FREE Sessions to meet a tutor and get help on any topic you want!

Pricing for Online Tutoring

Tutoring PackageValidityGrade (1-12), College
5 sessions1 Month$139
1 session1 Month$28
10 sessions3 months$269
15 sessions3 months$399
20 sessions4 months$499
50 sessions6 months$1189
100 sessions12 months$2249

Images Credit: