Ag in Action: Learning with Pigs – Structure and Function

Target Grade Level / Age Range:


Estimated Time:

               35-50 minutes depending on depth


In this lesson students explore different structures of a pig and their functions as they draw connections to a pig's lifecycle and behavior. 


Essential Files (maps, charts, pictures, or documents)


  • Pastern: the part of the pig located just below the dewclaws and above the pig hooves.  
  • Jowl: the part of the pig that is under the snout and is also known as the pig’s chin 
  • Snout: also called the nose of the pig is located by the mouth. It is used by the pig to move, turn, and lift objects; as well as to assist in eating and smelling. The size and length of the snout varies from breed to breed. 
  • Hock: located on the rear legs and are located just below the stifle muscle of a pig. The hock is a muscle that helps the pig move.  
  • Masseter: a muscle found in humans, horses, pigs, and other animals that have jaws. This muscle helps to move the jawbone for chewing. 
  • Zygomaticus: a muscle that attaches to the zygomatic bone. It helps to move muscles in the face including eye movement and chewing. 
  • Phalanges: the bones that help to provide support for the pig’s toes to provide support and stability when walking. Similar bones make up fingers and toes in humans. 
  • Ball and socket joint: this joint helps to provide rotation and movement.  
  • Ear drum: a membrane in the inner ear that vibrates when sound waves hit it. These waves are passed on as vibrations to other parts of the inner ear to finally be interpreted by the brain. 
  • Ear canal: a part of the inner ear that funnels sound to the ear drum. This part of the ear also contains tiny hairs that help to move sound waves.  
  • Cochlea: a part of the inner ear that contains fluid- and tiny hairs which transfer sound waves to the auditory nerve and the brain.  
  • Nostril: the opening of the snout that air goes through for respiration and sensory. 


Background – Agricultural Connections

Pig EARs are located just above the eyes and in front of the neck. The pig's ears can vary in shape and size. The outside of the ear helps to funnel sound waves into the ear canal. The ear canal leads to the ear drum which vibrates at varying speeds based on the length of the sound wave. When the ear drum vibrates, the movement is transferred to other parts of the inner ear like the cochlea. At the cochlea, the sound waves are transferred to a liquid which helps to move tiny hairs. This movement sends information to the auditory nerve and finally to the brain to be interpreted. The ears help with survival by allowing the pig to gather information about their world. For example, when a piglet can hear their mother, they have a better chance of finding food. Hearing also allows pigs to identify and recognize danger so they can react (behavior). In agriculture, farmers will notch their ears to help them identify each pig. Having a way to identify each pig helps the farmer keep records such as genetic information. This information can be used to breed pigs to make sure the offspring have the best traits.  

The pig’s SNOUT is a key feature that helps it smell and gather information about its world. The length of the snout varies from breed to breed and has two openings called nostrils. The nostrils provide a way for air transfer to occur. This includes the intake of oxygen and expulsion of carbon dioxide (survival). Air also contains particles. The snout can help filter out these particles using tiny hairs to catch things like dust (survival). Smaller particles, like scent molecules, are captured by receptors in the pig's snout. This molecule works like a light switch triggering the pig’s brain. If the pig had engaged with the item before, it recognizes the smell; if not, the pig will create a memory. The ability to recognize and remember certain scents helps the pig find food, litter mates, and detect danger. The snout also helps the pig to move dirt and other items (behavior, survival, growth), much like humans using their hands. Scent also helps a male know when a female is in heat (reproduction).  

The pig’s JOWL is located under the snout and is also known as the pig’s chin. Muscles (masseter and zygomaticus) that connect to the bones of the jowl help to move the bone, allowing the pig to chew (survival, behavior). Pigs are omnivores, but farmers feed their pigs a ration of corn, soybeans, vitamins, and minerals. Being able to chew their food gives pigs the ability to gather matter which is transformed into energy in the pig's body (growth, survival). In wild pigs, the female will use her mouth to clean off the piglets after they are born. By cleaning her young, the mother pig helps the piglets dry quicker which helps to keep the piglets from getting chilled (reproduction, behavior).  

Pig HAM is a cut of meat that is made up of the biceps femoris and other muscle layers. These muscles help to move the skeletal system, or bones, of the pig. When bones come together, they create joints. A ball and socket joint is one of four common joints found in animals with skeletal systems. Other joints include pivot, hinge, and sliding. These joints can also be found in humans and other animals. The ball and socket joint has a large range of movement allowing the pig to walk or run with ease (survival, behavior, reproduction). Being able to move with ease helps the pig strengthen their muscles and support their bodies as they grow 

The pig PASTERN is located just below the dewclaws and above the pig's hooves. The pastern provides the pig support as they walk through their skeletal system. The bones in the pastern are known as phalanges. Having a strong and sturdy skeletal structure helps provide support for the pig as it grows and puts on weight. It also helps to support the pig as it moves over different terrain (behavior). In modern agriculture, many pigs are raised in hog barns that have cement floors with slats. Having strong bones means that the pig will be able to avoid injury when standing or walking on a harder surface like cement (survival).

Interest Approach – Engagement (10 minutes)

  • Discuss with students that you’re going to play a group trivia game as a class. 
  • Determine one side of the room to be Truth and the other side to be Hogwash. 
  • Ask students what truth means.  
    • In this activity “truth” relates to a fact  
  • Ask students what hogwash means. Discuss with students that pigs used to eat a lot of different things like acorns, grass, and even table scraps. This led to the word “hogwash”.  
  • Remind students of the two sides of the room, one for “truth” and the other for “hogwash”. 
  • Read the Truth or Hogwash questions to students. If they think a question is “truth” have them move to that side of the room. If they think the question is “hogwash” have them move to that side of the room.  
    • Alternatively, have students give a thumbs up (truth) or a thumbs down (hogwash) 
  • After reading a question and students answering, discuss with students the background information provided with the answer. Repeat this process until all questions have been discussed. 
  • The final question is about pig eyesight. Ask students if they think having poor eyesight could affect a pig's survival. How about their behavior? 
    • Potential student answers: when animals can’t see well, they’ll often compensate by using other structures of their body to learn about their world. Pigs will often use their snout and sense of smell to find and recognize other pigs. They’ll use their bodies and ears to feel and hear where other pigs are. 
  • Let students know that they are going to be scientists and investigate different structures of pigs and how those can affect how the pig functions. 


Explore/Explain (15-20)

  • On the board make a table with columns labeled, Survival, Growth, Behavior, Reproduction, and rows labeled ear, snout, jaw, pastern, and ham. 
  • Discuss with students that they’ll be working like scientists today, and that sometimes scientists work in small groups to gather data for a larger group. Split the students into groups so that each group has a pig structure to investigate. Handout the Pig Structure Investigation sheets to groups. 
  • Give students time to investigate and gather data using the Pig Structure Data sheet that corresponds to their Pig Structure Investigation sheet.  
  • Once time is up, have students share from their groups what they discovered by creating a poster. Their posters should include information about their structure and how that structure helps the pig function (question on their data sheet).  
  • Have students hang their posters on the wall. Have groups rotate from one poster to the other in a gallery walk.  
  • After the gallery walk, bring the class together as a whole group. Let students know that once scientists see what others have found, they’ll come together as a whole group.  
  • Work as a class to fill out the data table on the board. You might ask students questions like; how do ears help with survival? What internal structures were a part of the ear? How does the snout help with growth or reproduction? etc. 
    • The posters and class data will be used to help students in the elaborate portion. 

Elaborate (10 minutes)

  • Read Hiccup the Wonder Pig, with students. While reading pause to review with students the different structures of a pig and how Hiccup is using or not able to use those structures (e.g., Hiccup’s head shakes which makes it hard for her to use her mouth (jaw), shaking made it hard to walk (ham/muscles), etc.).  
  • Discuss with students that when certain structures of an animal's body are different, the function might also change. Ask students if they can think of ways Hiccup’s behavior was different from others (e.g., shaking) or growth (e.g., Hiccup still grew just like her siblings). Ask students how the farmer helped Hiccup and provided care for Hiccup (e.g., warmth, food, etc.). 
    • (Optional) Let students know that farmers will work with livestock veterinarians. Livestock veterinarians help to research and take care of animals that might be sick. Show students the Livestock Veterinarian poster. Read the information about Dr. Cara Hadan. Ask students the question prompt on the poster, “What problems could livestock veterinarians solve?”  
      • Potential student answers: diagnosing sick pigs, fixing broken bones, vaccinations, feed rations 
    • Ask students how Dr. Hadan might help Hiccup. Discuss with them the different ways that a veterinarian can help pigs.  
  • After the discussion, students write an argument of what structure (1-2) they think a piglet couldn’t live without and why. 
    • Using the Claim, Evidence, Reasoning structure can help guide students. Also, encourage them to look back at the classes data and think back to their own data.

Evaluate (5 minutes)

  • At the end of the lesson review with students how the different structures a pig has affect the ways they function.  

Did you know? (Ag facts)

  • Humans and pigs have a lot of body structures in common. That’s why scientific research will use pigs as a model animal and why we can use pig heart valves in human medicine! 
  • Some pork producers will place items in the pens with their pigs so they can do rutting behavior with their snout.   
  • Female pigs called sows, are pregnant for three months, three weeks, and three days! 

Extension Activities

  • Engage students with plant structures and functions. Have students recognize patterns between plants and animals as they investigate internal and external structures. 
  • Engage with a FarmChat by requesting one from your local AITC coordinator or the IALF team. 
  • Explore how pork production has changed over time with the Ag in Action: Learning with Pigs Lesson 2. 

Suggested Companion Resources




Cathryn Carney  

Organization Affiliation

Iowa Agriculture Literacy Foundation

Agriculture Literacy Outcomes

  • T2.3-5.d. Provide examples of specific ways farmers/ranchers meet the needs of animals.

Iowa Core Standards

  • Science
    1. 4-LS1-1. Construct an argument that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction.