As much as we want to spend time with our pets, we can't devote every moment to them. Yes, they're huge parts of our lives, but there's work, shopping, and other nonsense we need to take care of. So every once in a while, we have to lift our hands from their furry tummies and focus our attention elsewhere.

However, the little rascals aren't always understanding. To showcase that, we at Bored Panda put together a list of pictures where cats, dogs, and other companion animals appear to be refusing to share their owners. Whether it's their threatening eyes or passive-aggressive paw placements, these goofballs seem to want everyone to know that their humans are theirs and no one else's.

#1 My Cat Cat Disapproves Of Human/Dog Love. I Didn't Even Know She Could Do That Face

Image credits: nanatalada

#2 This Is Roger. He Gets Jealous Of His Human Baby Brother. Acts Out By Stealing Pacifiers And Demanding To Be Held

Image credits: dog_rates

Despite these pictures and other anecdotal evidence, scientists have long struggled to identify emotions in animals, especially because of the difficulty in separating out biases and anthropomorphisms.

That being said, research is starting to suggest that jealousy, at least, is a "primordial" emotion that both people and some animals (particularly dogs and primates) share.

#3 My Dane Is Jealous Of A Hamster Eating His Kibble

Image credits: CharlesDrake

#4 Jealous Of The New Member Of The Home

Image credits: fatihcik

#5 GF And I Were Holding Hands. Then This Happened

Image credits: abilledeaux

Before we dive in deeper, it's important to understand that while the terms jealousy and envy are sometimes used interchangeably, psychologists see them as two very different emotions.

Envy is thought to be a two-entity emotion that occurs when we lack something — whether it's a specific personal attribute or an object — that someone else has. Jealousy, on the other hand, requires a social triangle and emerges when someone or something threatens a special relationship.

#6 This Is Athena, She Is A 9-Year-Old Labrador. As You Can See She's A Chunker But She Gets Jealous When She Sees Our Smaller Dogs On Our Laps And Throws A Fit

So of course I have succumbed to her commands.

Image credits: Martinstanley12

#7 This Is What Stages Of Jealousy Look Like

Image credits: Rawtashk

#8 My In-Law's Dogs Posed So Well With My Wife For A Picture, But Our Dog Got Jealous And Wanted To Be In The Shot Too

Image credits: Mapes

#9 Taking Photos Of My 5-Month-Old Baby And Sammy Got Jealous

I was squatting down to take pictures and my dog jumped up onto my leg and leaned in. I kept taking pictures. This was a later picture when he wasn't getting the attention he wanted so he got that hilarious desperate look in his eye.

Image credits: canuchangeusernames

For someone to feel jealousy, they need to have the cognitive ability to recognize, at least on some level, the importance of a relationship and gauge potential threats to it — a tall order, no doubt.

In humans, research shows that infants as young as 6 months demonstrated it when their mothers interacted with another infant (which was, in reality, a realistic-looking doll). This suggests that jealousy can be an inborn (not learned) emotion that evolved to protect any type of social relationship from interlopers, and one that may exist in other social animals.

#10 4 Day Old Baby + A Jealous Cat = Cutest Snuggles

Image credits: catlover3434

#11 My Dog Got Way Too Jealous When I Was Cuddling With My Cat. Walked Over, Nudged Him Off Me, Then Just Laid On Top Of Him

Image credits: rachar2187

#12 He Gets Jealous When We Try To Play With His Buddy

Image credits: parentsti

#13 Missing Out On The Kisses

Image credits: xSpiderBabyx

In 2014, researchers at the University of California, San Diego modified human infant experiments, adapting them to man's best friend.

They found that dogs acted far more jealous when their owners interacted with a fake dog (petting it and treating it as if it were real) than with jack-o'-lanterns or books. In fact, one-third of the dogs tried to get in between their owners and the fake dog, and one-fourth of them even snapped at the fake dog.

#14 Someone Was Jealous

Image credits: chasinafterhappiness

#15 I Was Already Cuddling Joni, Then Nico Got Jealous And Plonked Himself On Top Of Her

Image credits: spome2

#16 My Niece Picked Her Name, So Meet Kiwi! That's Cruz Down There Jealous He Can't Also Be Carried Around

Image credits: buhfuhkin

#17 I Think My Dog Is Jealous Of The Baby

Image credits: Huckleberry_Rogers

Scientists have also documented jealousy in coppery titi monkeys, a monogamous primate species.

In response to romantic rivals, male titi monkeys are known to become aggressive, place themselves between their mates and potential rivals, and occasionally physically restrain their mates to keep them from moving toward intruder males.

#18 Someone Is Jealous Of The Attention My Baby Brother Was Getting

Image credits: defenseman13

#19 Someone Is Jealous

Image credits: wantganja420

#20 My Pup Gets Jealous When I'm Photographing People And Feels The Need To Get Involved

Image credits: BeerBellies

#21 My Brother-In-Law’s Dog Gets Jealous When They Take Monthly Pictures Of Their New Baby. So They Found A Solution

Image credits: TearsOfARapper84

The scientists had male titi monkeys watch their mates interact with stranger males for 30 minutes as well as watch stranger females interact with stranger males for the same amount of time.

When observing their mates, the monkeys experienced increased levels of the hormones testosterone (associated with mate-related aggression and competition) and cortisol (an indication of social stress).

#22 Uh-Oh, Looks Like Some Calf Is A Little Jealous Of Emmett Playing With The Rabbit

Image credits: ctfarmstead

#23 Someone Was Jealous She Wasn't Getting Pats

Image credits: WhenWhereWho

#24 The Cat Went For A Belly Rub. The Dog Got Jealous. Now This Is Happening

Image credits: veschwab

#25 Someone Was Jealous Of His Much Smaller Brother’s Bed. Yes, He Has His Own Perfectly Good Bed

Image credits: Aprilismissing

Brain scans also revealed the primates had heightened activity in an area associated with social exclusion in humans (the cingulate cortex) and another area associated with aggressive behavior (the lateral septum).

#26 Sophie To The Right Was A Little Jealous Meeting Her New Baby Sister Coco

Image credits: Hutlet

#27 Reached Over To Hold My Wife's Hand And Someone Immediately Got Jealous

Image credits: mrfu709

#28 Update On My Parents' Cat That Was Jealous Of The Grandbaby's Birthday Present. He Now Has His Own $30 Children's Chair, Just To Settle Things

Image credits: hangry_lady

#29 My Husband Trying To Watch TV Last Night. Wimpy And Buddy Competing For The #1 Spot In The Bed. Guess Who Won

Image credits: christypawpersians

Complementing these pictures, a large percentage of pet owners report consistent signs of jealousy in other domestic pets, including horses, birds, and cats.

For more "evidence", check out Bored Panda's earlier piece 50 Shameless Pets That Stole Their Owners’ Partners And Didn’t Even Feel Sorry About It.

#30 My Uncle Found A Bird. His Cat Is Jealous

Image credits: reddit.com

#31 Quick Sticks Feeling Very Zen In Her Special Whippet Coat. Please Ignore The Jealous Stares Of The Sausage In The Background

Image credits: Patchspot

#32 Someone Is Jealous

Image credits: estacaoteimosa878

#33 Went To Take A Picture Of My Puppy, And Captured My Jealous Cat In The Background

Image credits: Missmayo

#34 Pretty Sure Somebody Is Jealous Of Our New Kitty

Image credits: amojuris

#35 My Husky Is Jealous Of My Fake Husky

Image credits: skycolylyly

#36 Tried To Take A Picture Of My Orchid. He Gets Jealous When I Give Anything Else Attention. See How He Lay Right Under The Flowers?

Image credits: MUM2RKG

#37 My Husband Telling Ferdinand, Our Senior Rescue Kitty, That He’s Now A Star After Over 115k Likes On His First-Ever Post. And The Dog, Well, The Dog Is Jealous

Image credits: tiffanymcclure

#38 Sums Up Their Relationship Pretty Well

Image credits: namanama101

#39 I Think My Cats Are A Little Jealous That I Am Outside With The Dog And Not Them

Image credits: reddit.com

#40 My Doggo, Willow, Got Jealous That I Was Taking A Pic Of My Swans And Not Her

Image credits: gkrichel

#41 We Got A New Cat. Let's Just Say That The Other One Was Very Jealous

Image credits: sdillon1015

#42 When The Two Friends You Introduced To Each Other Start Hanging Out Without You

Image credits: brennan.schulze

#43 Every Morning My Stepdad's Cat, Shiba, Sits On His Lap And Reads The Paper With Him. Back At Christmas, My Stepdad Met His Granddaughter For The First Time

And Shiba got a little jealous.

Image credits: leeannivey

#44 The Dog Was Jealous Of The Baby, So

Image credits: jpkitchener

#45 Serious Jealousy Over The Snuggles, Apparently

Image credits: nazigrammar42

#46 My Wife's Dog, Koda, Jealously Guarding Her While She Sleeps. Best Pup

Image credits: Badbomber360

#47 Why Is He Getting All The Attention?

Image credits: KaySheedy

#48 I Think Someone’s Jealous

Image credits: fiddle_sticks_

#49 I Am Such A Jealous Cat When It Comes To Time With My Dad Lately

Image credits: andthepetshaveit

#50 Why Are You Petting Him And Not Me?

Image credits: reddit.com