We all know dogs are (hu)man's best friend.

Our pets keep us company, take us on adventures, and teach us about unconditional love. In return, we give them food and shelter and train them to do silly things.

This mutt does a mean "roll over."

But service and working dogs take their relationship with humans a step further — these pups are trained with skills that can save lives. Did you know that some dogs can detect allergens in your food? And get help in an emergency situation?

Here are 13 impressive things service and working dogs can be trained to do that help save lives:

1. Smell blood sugar levels.

When blood sugar levels change, the human body releases chemicals that dogs can smell. Diabetic-alert dogs are trained to smell when their partner's blood sugar level is dangerously off and to let them know that action is needed to get those levels back in the safe zone.

Luke, a boy with Type 1 diabetes, has a diabetic-alert dog named Jedi, who alerted him to low glucose levels:

2. Find a person buried in an avalanche.

If you're ever caught in an avalanche, having a dog on the search-and-rescue team could drastically increase your chances of survival. An avalanche dog can search 2.5 acres in 30 minutes. (It would take a team of humans up to four hours to cover the same ground.) These skilled canines sniff the snow for a pool of human scent; when they find it, they alert their handler and start digging.

Keena the avalanche pup is training in Colorado:

3. Alert you to the sound of a fire alarm.

Hearing dogs are trained to assist people who are deaf or hard of hearing. These pups alert their partners to a wide variety of sounds: a door knock, a spoken name, an alarm clock, a fire alarm, and more.

Like any service dog, hearing dogs require years of committed training to perform their tasks. But even these furballs — like Sophie the collie/lab mix — need a little down time!

4. Support someone who has PTSD.

A post-traumatic stress disorder service dog can detect early signs of anxiety then nudge, paw, lick, and generally distract their human from potential triggers in the environment, giving their partner a chance to regain control.

5. Detect changes in blood pressure.

When a person's blood pressure or heartbeat changes rapidly, a cardiac-alert dog can warn the person of this danger. Without this signal, people with conditions like dysautonomia risk passing out (among many other complications) due to severe blood pressure changes.

Here, medical-alert dog Blaine cuddles with his handler:

6. Get help in an emergency situation.

Many service dogs can be trained to summon help in an emergency situation, whether it's finding another person to assist their human or using a special phone to call 911.

7. Protect people during seizures.

Some seizure dogs are trained to alert their handler before a seizure (similar to a cardiac-alert dog) while others respond a certain way during or after a seizure — such as barking for help, moving away certain objects that could be dangerous, or protecting their human as they collapse.

This adorable mug belongs to Riley, a seizure-alert and response dog:

8. Deliver medical supplies to injured soldiers.

During World War I, "mercy dogs" were trained to search a battlefield for wounded soldiers. The dogs carried packs with medical supplies that soldiers could use to treat their own injuries. Some dogs were trained to retrieve a handler to assist the injured soldier.

Below, Lt. Col. Edwin H. Richardson poses with Red Cross war dogs during World War I:

Image via Library of Congress.

9. Detect potential allergens in food.

Some people don't like peanuts. Some people go into anaphylactic shock and risk serious health complications or even death if they touch peanuts.

For the latter, allergy detection dogs can be trained to sniff out allergens like peanuts, milk, soy, latex, or other substances. The pup can alert their human of the danger or even block the person from going near the allergen.

10. Support someone with autism.

Autism service dogs provide crucial companionship for their partners, and some are trained to alert and respond to certain triggers. For example, if a human has trouble with anxiety or sensory processing, their pup can provide calming comfort by lying on top of them — a technique called "deep pressure therapy."

Ultron, an autism service dog in training, helps his partner Axton navigate the world more confidently and independently:

11. Guide a person who is visually impaired.

Guide dogs are loyal pups who are trained to help those who are blind or visually impaired physically navigate the world. Humans have been training dogs for this purpose for centuries, and the practice of dogs helping guide people is actually so old that we'll never really know how or when it began.

This little guide dog in training, Smudge, isn't quite big enough for her harness yet:

12. Sniff out explosives.

Bomb-sniffing dogs alert their handler if they smell even a small amount of explosives. These dogs are common in the military, but they also save lives working with organizations like the United Nations Mine Action Service. UNMAS uses mine detection dogs to de-mine conflict-heavy places, including Colombia and Sudan.

13. Provide physical balance and support.

Brace and mobility service dogs help their humans physically get around by opening doors, picking things up off the ground, helping their partners up from a fall, providing counterbalancing or bracing while walking, and more.

Here you can clearly see service dog Kaline's mobility harness:

People tend to talk about how fortunate dogs are to have devoted humans looking out for them. We spend years training them and thousands of dollars on food, vet visits, cute outfits (don't deny it), and treats — the list goes on.

But as lucky as dogs are to have us, we're infinitely more lucky to have them sticking with us every step of the way.