Smorgasbord Blog Magazine Share Superfact 21 – Neutering or spaying a dog at 6 months old can be dangerous to their health depending on breed

I was very happy when I saw the post above. Sally is sharing my super fact 21: Superfact 21: It is often recommended that you should neuter or spay your dog by the age of 6 months even as early as 8 weeks. This may be OK for some smaller breeds but is dangerous to the health and longevity of many larger breeds. In addition, she is promoting my Leonberger dog book for which Robbie wrote a great review. Thank you so much Sally and Robbie. Please visit her post at the Smorgasbord blog magazine and read it.

Neutering or spaying a dog at 6 months old can be dangerous to their health depending on breed

30-60 million Bison used to roam the plains

Super fact 110 : At the end of the 18th century there were 30-60 million North American Bison (buffalo) roaming the plains. The mass destruction of the bison began in 1830 and was intentional and by the end of the 19th century there were only a few hundred left. Since then, they have recovered and today there are 500,000 Bison including 30,000 wild Bison.

The picture shows a male plains bison standing on a plain and looking into the camera.
Scientists are helping users of American rangelands meet the challenge of managing multiple uses and sustainably. This picture is in the public domain because it contains materials that originally came from the Agricultural Research Service, the research agency of the United States Department of Agriculture. From Wikimedia commons author Jack Dykinga.

In the past there were at least 30-60 million bison, roaming North America. As mentioned by the end of the 19th century there were only a few hundred left. They have recovered since then and now there are 500,000 Bison including 30,000 wild Bison. For comparison there are 86.2 million cattle in the US  and another 11.8 million in Canada. This is just one of many reasons that the wild mammal biomass has substantially declined around the world. Wild mammals have declined by 85% since the rise of humans even as the total mammal biomass has nearly tripled.

The reason for the extremely sharp decline of the Bison in the 19th century was because the U.S. government intentionally drove the bison to the brink of extinction. The American bison was a major resource for the traditional way of life of the native Americans and therefore the extermination of the Bison became an important tool in the efforts to subjugate Native Americans.

30-60 million Bison used to roam the plains | 1892: bison skulls await industrial processing at Michigan Carbon Works in Rougeville (a suburb of Detroit). Bones were processed to be used for glue, fertilizer, dye/tint/ink, or were burned to create "bone char" which was an important component for sugar refining. In the 16th century, North America contained 25–30 million buffalo.
1892: bison skulls await industrial processing at Michigan Carbon Works in Rougeville (a suburb of Detroit). Bones were processed to be used for glue, fertilizer, dye/tint/ink, or were burned to create “bone char” which was an important component for sugar refining. In the 16th century, North America contained 25–30 million buffalo. This picture is in the public domain and taken from this Wikipedia.

I consider this a super fact because it is a shocking historical event that it seems many are unaware of. I was certainly surprised the first time I read about it.

How Did the Bison Population Recover ?

At the end of the 19th century indigenous groups used the Flathead Indian Reservation to quietly protect small captive herds, keeping bison alive while they vanished from the wild. In addition, a few individuals as well as Native American families captured stray calves and started private breeding programs.


A herd of grazing bison on a field in Yellowstone. In the background are geysers and hills.
Herd of American bison grazing in a green meadow at Yellowstone National Park, with geysers and mountains in the background under a bright blue sky. Shutterstock asset id: asset id: 2688666937 by NicoleHFlores



To see the other Super Facts click here

Mosquitos and Snakes Kill Hundreds of Thousands of People Annually

Super fact 98 : The deadliest animals in the world are mosquitos, snakes and dogs. Mosquitos kill an estimated 760,000 people each year. Snakes kill an estimated 100,000 people each year. Dogs kill an estimated 40,000 people each year. By comparison humans kill on average 600,000 other humans annually due to wars and violence.

The picture feature purple bar graphs with animal pictures and animal names. The numbers indicate the number of people killed each year (well 2023) by an animal. The numbers are Mosquitos 760,000, Humans 600,000, Snakes 100,000, Dogs 40,000, Freshwater Snails 14,000, Kissing bugs 8,000, Sandflies 5,000, Roundworms 4,000, Scorpions 3,000, Tapeworms 2,000, Tsetse flies 1,500, Elephants 1,000, Bees, wasps and hornets 500, Big cats 300, Crocodiles > 150, Jellyfish 100, Hippopotamuses > 50, Spiders 50, Bears 20, Sharks 6, Gray wolves 5.
Estimates for the number of humans killed by different animals in 2023. Note: This is not an exhaustive list. Estimates come with significant uncertainty and are used for relative magnitude comparisons. Figures have been rounded to not overstate accuracy. Data sources: IHME; GBD (2025); World Health Organization; CrocAttack; ISAF; and others. See the full documentation at https://docs.owid.io/projects/etl/analyses/deadliest_animals/   OurWorldInData –  Research and data to make progress against the world’s largest problems.  Licensed under CC-BY by the authors Hannah Ritchie and Fiona Spooner.

The first time I heard that the deadliest animal in the world was the mosquito I was surprised. After I heard that the reason was all the diseases that mosquitos spread, such as malaria, dengue fever, and yellow fever, it made more sense to me. I recently learned that snakes kill 100,000 people every year. It surprised me because it seemed like a lot to me.

I was also surprised to learn that our best friends the dogs, come in as number three on the list of deadliest animals, at an annual kill rate of 40,000 people. Even though scorpions are not at the top of the list they kill 3,000 people annually, while spiders only kill 50 people. We have both venomous spiders and scorpions where I live, but I’ve been worried about spiders, not scorpions. It is also surprising to me that sharks only kill about 6 people per year. I guess my super fact 98 is a collection of facts regarding “killer animals” rather than one specific fact. I am hoping that at least one of the facts will be surprising to you.

I should mention that the numbers vary over time and different sources give different statistics. Therefore, the numbers should be seen as ballpark numbers and not exactly. However, Our World in Data is considered one reputable and highly reliable data source that is frequently cited in scientific journals, and access is free.

Mosquitos Kill 760,000 People Each Year

Mosquitos are the biggest killers of humans by far. 80% of those deaths are the result of malaria which is transmitted and spread by the Anopheles mosquito. We have made progress against malaria, and it used to be worse. In the 20th century 150 to 200 million people died from malaria, which is more than one and half million people per year. Smallpox killed 300 million people in the 20th century, but it was entirely eradicated by 1977 thanks to the smallpox vaccine. The two existing vaccines for malaria are relatively recent (2021 & 2023), not as effective as the smallpox vaccine was, and not yet as widely used, which is one reason malaria is still a major health concern.

The picture shows a mosquito biting human skin. It is already filled up with blood. | Mosquitos and Snakes Kill Hundreds of Thousands of People Annually
The Aedes aegypti mosquito, which spreads dengue fever and yellow fever. Original author: US Department of Agriculture; then denoised rescaled, enhanced with adaptive denoising filters and minimal resharpening, then unscaled to original resolution, for easier refitting at various resolutions., Public domain, via Wikimedia Commons.

In addition, mosquitos spread other diseases killing more than 100,000 people every year. Dengue fever, yellow fever and Japanese encephalitis, are a few of the more dangerous mosquito borne diseases.

Snakes Kill 100,000 People Each Year

The death toll from venomous snakes is uncertain but it is likely to be 100,000 deaths per year. The World Health Organization estimates that snake bites kill between 81,410 and 137,880 each year.

The most venomous snake in the world is the Inland Taipan. Its venom can kill over 100 people in a single bite. However, due to its shy nature and remote Australian habitat, no human deaths have been attributed to it. The most dangerous snake to humans, in terms of fatalities, is often considered the Russell’s viper, responsible for 25,000 deaths annually. Other snakes that kill several thousand people every year are the saw-scaled viper, the common krait, the Indian cobra in Asia, and the black mamba.

The photo shows a brown speckled snake with a head that does not appear wider than the body unlike the head of vipers. | Mosquitos and Snakes Kill Hundreds of Thousands of People Annually
Inland Taipan. XLerate, CC BY-SA 3.0 http://creativecommons.org/licenses/by-sa/3.0/, via Wikimedia Commons.
The photo shows a light brown snake with dark brown spots and triangular viper head. | Mosquitos and Snakes Kill Hundreds of Thousands of People Annually
Russel’s Viper in the CME Dapodi campus. Photographed by Abhinav Chawla (self). AChawla, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons.
A beige spectacled cobra with flared hood looking into the camera. | Mosquitos and Snakes Kill Hundreds of Thousands of People Annually
The Indian Cobra, here photographed at Hoskote, Karnataka, is one of the most dangerous snakes in all of Asia. Pavan Kumar N, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0&gt;, via Wikimedia Commons.

Dogs Kill 40,000 People Each Year

Our mini-Australian Shepherd puppy Rollo is lying on a blanket.
Did you kill 40,000 people? Actually, our mini-Australian Shepherd Rollo did not kill anybody.

Even though there are some large and dangerous dogs, most deaths caused by dogs is from rabies resulting from being bitten by a rabies infected dog. See the horror movie Cujo.

Freshwater Snails, Kissing Bugs, Sandflies, Roundworms are Mass Killers

Other critters that kill thousand of people every year are freshwater snails, kissing bugs, sandflies, and roundworms. These critters kill people by infecting them with dangerous parasites or as in the case of roundworms, being a dangerous parasite.

Scorpions Kill 3,000 People Each Year but Spiders Only 50

I was at an overnight outing with the guys at work. I had just moved to Texas. We were standing or sitting around the fire drinking beer when I asked a question. I’ve heard about the scorpions in Texas, but I’ve never seen any. How common are scorpions?

A coworker named Gary told me to turn around, so I did. Behind me was a tree, and the tree was covered by crawling scorpions. Well, I was glad I did not lean on it. The scorpions I saw were the striped bark scorpion.

The reason scorpions kill a lot more people than spiders is that some scorpion species have a very potent and deadly venom. Some spiders are dangerous too, but spiders tend to have less potent venom.

A yellow, beige scorpion with light brown stripes.
Striped Bark Scorpion (Centruroides vittatus) Striped Bark Scorpion (Centruroides vittatus). Charles & Clint, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons.

The Big Cats kill only 300 People Annually and Sharks Only 6

Would you prefer to stay in a room with a Tiger or with a mosquito? Mosquitos kill 760,000 people every year, whilst Tigers only kill a handful of people every year. However, Tigers don’t kill less people than mosquitos because they are less dangerous than mosquitos. The difference is exposure. Mosquitos are everywhere but not Tigers. If Tigers were as common as people and everywhere people were, the numbers probably would be different.

Bengal Tiger walking next to a forest.
Bengal tiger (Panthera tigris tigris) female, Kanha National Park, India. Attribution: Charles James Sharp.

Other Posts Related to Animals




To see the other Super Facts click here

The Evolution of Whales is No Longer a Mystery

Super fact 85 : Scientists recognized that whales descended from land animals already in the 19th century. However, it was not until the 1980’s that intermediate fossils for whale evolution were found. In addition, molecular and genetic / DNA studies showed that Hippopotamus and whales were closely related. Until then the evolution of whales was a bit of a mystery and creationists frequently mocked the lack of intermediate fossils for whale evolution.

This graph shows pictures of a sperm whale, gray whale and hippopotamus on the right, and two whale ancestors at the top and they are connected via lines ultimately showing the common connection point on the far left. | The Evolution of Whales is No Longer a Mystery
All living cetaceans including whales, dolphins, porpoises, sperm whales and hippopotamids / hippopotamus belong to a suborder of artiodactyls called whippomorpha. Just like humans and chimpanzees have a common ancestor hippopotamus and whales have a common ancestor. Note: I created this image by inserting a few pictures from Wikipedia commons including a mother sperm whale and her calf off the coast of Mauritius, a gray whale in captivity, a hippopotamus and two pre-historic whales (from the section Evolution of Whales – Intermediate Fossils). All pictures are shown below.
The picture shows a mother and  calf sperm whale swimming in the ocean.
Sperm whales from Wikimedia commons. A mother sperm whale and her calf off the coast of Mauritius. The calf has remoras attached to its body.
The picture shows a gray whale in water. | The Evolution of Whales is No Longer a Mystery
A gray whale in captivity. Marine Mammal Commission, Public domain, via Wikimedia Commons.
Portrait of a Hippopotamus in water in Saadani National Park. Muhammad Mahdi Karim, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons.

Scientists realized hundreds of years ago that whales were a lot more like mammals than fish, in fact they were mammals. However, the fact that no intermediate fossils between land dwelling mammals and whales had been found presented a mystery and attracted the mockery by creationists. It was said that there was a missing link. Then intermediate fossils were found, and then a lot more of them.

In addition, DNA analysis of modern whales and hippopotamus showed that they were related and had a common ancestor. Just like chimpanzees and humans have a common ancestor, but chimpanzees are not an ancestor to humans, hippopotamus and whales have a common ancestor, but whales did not evolve from hippopotamus. To read more about the evolution of whales click here, or here, or here, or here, or here, or here, or here.

The thing with gaps in the fossil record or so called missing links is that as they are filled out new gaps are created, smaller gaps. Therefore, you can always claim that there are gaps. So be careful when you hear creationists speaking of missing links or gaps in the fossil record. Instead focus on the intermediate fossils that we have found and keep finding.

The fact that we’ve found a lot of intermediate fossils for the evolution of whales and that DNA tells us that Hippos and Whales are related and have a common ancestor probably comes as a surprise to many. It was certainly a surprise to me when I heard it the first time. It is true and kind of important to know. Therefore, I consider this a super fact.

Evolution of Whales – Intermediate Fossils

The first intermediate fossil found between land mammals and whales was Pakicetus found in Pakistan in 1983. You may wonder how we know that Pakicetus was related to whales. This evidence includes its fossilized ear bone (auditory bulla), which possesses a unique, thickened shape called an involucrum that is found only in cetaceans. Pakicetus also shares whale-like teeth, an ankle bone and a skull structure similar to other early whale like creaturs. Since the discovery of Pakicetus a lot more whale ancestors (intermediate fossils) have been found. Below is a list with illustrations of the various intermediate fossils.

Pakicetus: The illustration shows a four legged carnivorous mammal with a tail and an elongated snout.
Pakicetus inachus, a whale ancestor from the Early Eocene of Pakistan, after Nummelai et al., (2006), pencil drawing, digital coloring. It lived 48-49 million years ago. Nobu Tamura (http://spinops.blogspot.com), CC BY 3.0 <https://creativecommons.org/licenses/by/3.0&gt;, via Wikimedia Commons.
Indohyus: The illustration shows a four legged carnivorous mammal with a tail and an elongated snout. | The Evolution of Whales is No Longer a Mystery
Indohyus major, a herbivorous whale ancestor from the Middle Eocene of Kashmir, pencil drawing, digital coloring. It lived 48-49 million years ago. Nobu Tamura (http://spinops.blogspot.com), CC BY 3.0 <https://creativecommons.org/licenses/by/3.0&gt;, via Wikimedia Commons.
Ambulocetus: The illustration shows a four legged carnivorous mammal with a tail and an elongated snout.
Ambulocetus natans, a primitive whale from the Early Eocene of Pakistan, pencil drawing, digital coloring. It lived 48-49 million years ago. Nobu Tamura (http://spinops.blogspot.com), CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons.
Kutchicetus: The illustration shows a carnivorous mammal with short legs, a tail and an elongated snout. It is swimming in the ocean.
Kutchicetus minimus, an early whale from the middle Eocene of India. Pencil drawing, digital coloring. It lived 48 million years ago. Nobu Tamura, CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons.
Remingtonocetus: The illustration shows a carnivorous mammal with short legs, a tail and an elongated snout. It is swimming in the ocean.
Remingtonocetus harudiniensis, an archaeocete whale from the Middle Eocene of India, pencil drawing, digital coloring. It lived 48 million years ago. Nobu Tamura (http://spinops.blogspot.com), CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons.
Maiacetus. It lived 47.5 million years ago. | The Evolution of Whales is No Longer a Mystery
Maiacetus. It lived 47.5 million years ago. Nobu Tamura (http://spinops.blogspot.com), CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons.
Rodhocetus: The illustration shows a mammal with short legs swimming in the ocean. It has flat feet, a tail and an elongated snout. It looks even more like a sea creature now.
Rodhocetus kasrani, an archaeoceti whale from the late Eocene of Pakistan, digital. It lived 45 million years ago. Nobu Tamura, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0&gt;, via Wikimedia Commons.
Dorudon: The illustration shows a mammal with fins swimming in the ocean. It has flat feet, a tail and an elongated snout. It looks even more like a sea creature now.
Dorudon atrox, an ancestral whale from the Late Eocene of Egypt, pencil drawing, digital coloring. It lived 35 million years ago. Nobu Tamura, CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons.
Aetiocetu: The illustration shows a fish or whale looking creature swimming in the ocean.
Aetiocetus cotylalveus, an early baleen whale from the Late Oligocene of Oregon, pencil drawing, digital coloring. It lived 27 million years ago. Nobu Tamura (http://spinops.blogspot.com), CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons.
Squalodon: The illustration shows a fish or dolphin looking creature swimming in the ocean. | The Evolution of Whales is No Longer a Mystery
Squalodon calvertensis, a toothed whale from the Late Miocene of North America, pencil drawing, digital coloring. It lived 25 million years ago. Nobu Tamura, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0&gt;, via Wikimedia Commons.
Janjucetus: The illustration shows a fish or whale looking creature swimming in the ocean.
Janjucetus hunderi, a Mysticeti whale from the Oligocene of Australia, digital work. It lived 25 million years ago.  Nobu Tamura   email:nobu.tamura@yahoo.com   http://www.palaeocritti.comderivative work: Niusereset, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0&gt;, via Wikimedia Commons.
Kentriodon: The illustration shows a dolphin looking creature swimming in the ocean.
Kentriodon pernix, an odontocete dolphin-like whale from the Miocene, pencil drawing, digital coloring. It lived 20 million years ago. Nobu Tamura (http://spinops.blogspot.com/2012/06/kentriodon-pernix.html?q=Kentriodon), CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons.
Aulophyseter: The illustration shows a creature that looks a bit like a sperm whale swimming in the ocean. | The Evolution of Whales is No Longer a Mystery
Aulophyseter morricei, a sperm whale from the Middle Miocene of California. It lived 20 million years ago. Nobu Tamura, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0&gt;, via Wikimedia Commons.
Cetotherium: The illustration shows a creature that looks like a modern gray whale swimming in the ocean.
Cetotherium furlongi, a baleen whale from the mid-Late Miocene of Europe, Russia and North America, digital. It lived 18 million years ago. Nobu Tamura (http://spinops.blogspot.com), CC BY 3.0 <https://creativecommons.org/licenses/by/3.0&gt;, via Wikimedia Commons.
Brygmophyseter: The illustration shows a creature that looks like a sperm whale swimming in the ocean.
Brygmophyseter shigensis (aka as Nagacetus shigensis), a sperm whale from the Mid Miocene of Japan. Digital. It lived 15 million years ago. Nobu Tamura (http://spinops.blogspot.com), CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons.



To see the other Super Facts click here

Birds are Avian Dinosaurs

Super fact 84 : Modern birds are classified as part of the clade Dinosauria. They are direct descendants of small, feathered maniraptoran dinosaurs that survived the Cretaceous-Paleogene extinction event 66 million years ago. Maniraptoran dinosaurs in turn are a major subgroup of coelurosaurian theropod dinosaurs. In other words, birds are avian dinosaurs.

3D illustration showing two carnivorous dinosaurs and two large herbivores looking up at a burning asteroid. | Birds are Avian Dinosaurs
Some dinosaurs survived the Cretaceous-Paleogene extinction event 66 million years ago. Shutterstock Asset id: 2196200279 by funstarts33

Birds are descendants of specialized maniraptoran theropod dinosaurs that survived the extinction event that killed most dinosaurs 66 million years ago. Maniraptoran dinosaurs in turn are a major subgroup of Tyrannoraptora, which include the well-known Tyrannosaurus Rex. Tyrannoraptora  in turn is a major subgroup of coelurosaurian theropod dinosaurs. Both the well-known dinosaur called velociraptor, and birds belong to the group Maniraptora. Even though the velociraptor was not a bird they shared many bird-like features, including feathers, wishbones, hollow bones, and similar wrist joints.

A colorful velociraptor covered in feather. It does not look like it could fly.
Velociraptor with feathers (well a little bit). Shutterstock Asset id: 2636534673 by Shutterstock AI Generator

Birds evolved during the Jurassic period from two-legged, carnivorous, and often feathered dinosaurs, and are the only surviving dinosaurs. They have been classified as avian dinosaurs since the 1980’s. In other words, they are dinosaurs. Initially feathers evolved among dinosaurs for insulation, sexual display, and camouflage rather than flight. One of the early birds was Eoconfuciusornis. It lived 131 million years ago, long before the Cretaceous-Paleogene extinction event 66 million years ago. Eoconfuciusornis could fly and it had colorful feathers.

A black bird with a long retrix / tail sitting on a tree. | Eoconfuciusornis 130 million years ago. | Birds are Avian Dinosaurs
Eoconfuciusornis 130 million years ago. Nobu Tamura, CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons

I brought up this fact in a recent post and I hinted that it was a super fact. It is true, surprising and kind of important. After all birds are all around us. In this post I am exploring the fact that birds are dinosaurs a little bit more than I did in my previous post. Below are a couple of modern birds.

A shoebill stork is a large gray-blue bird with a huge beak.
A shoebill stork standing at Ueno Zoo, Tokyo, five feet tall. Bob Owen, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons
A taxidermy mount of a turkey standing on our dining room table. | Birds are Avian Dinosaurs
A wild turkey in our dining room.

Feathered Dinosaurs

A lot of dinosaurs had feathers, and some could fly. That included many types of dinosaurs other than birds. Dinosaurs with feathers include, for example, Velociraptor, Deinonychus, Archaeopteryx (could fly), Microraptor (could fly), Rahonavis (could fly), Gallimimus, Ornithomimus, Yutyrannus huali, Psittacosaurus, Psittacosaurus, Sinosauropteryx, Sinornithosaurus, Eoconfuciusornis, Wulong, Psittacosaurus, Sciurumimus, Kulindadromeus, Caudipteryx, Utahraptor, Deinonychus, and even young T-Rex and many others. We know that at least some dinosaurs had feathers as well as colors based on fossil finds. Below are some illustrations.

A Gallimimus dinosaur covered in hair and feathers.
Life restoration showing an adult with feathers, based on those known from the related Ornithomimus. Picture is from here. PaleoNeolitic, CC BY 4.0 https://creativecommons.org/licenses/by/4.0, via Wikimedia Commons
A bird like dinosaur with feathers. It has huge claws.
Life restoration of Pyroraptor olympius. Picture is from here. Mette Aumala, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons.
Birds are Avian Dinosaurs | Reconstruction of the 2014 microraptorine dromaeosaur dinosaur, Changyuraptor yangi. This is a dinosaur with four wings.
Reconstruction of the 2014 microraptorine dromaeosaur dinosaur, Changyuraptor yangi. This is a dinosaur with four wings. The picture is taken from here. Emily Willoughby (e.deinonychus@gmail.com, http://emilywilloughby.com), CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons
Greyish bird like creature with a reptile like head.
Artistic restoration of D. albertensis Artistic restoration of D. albertensis. Picture from here. Fred Wierum, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons
Six dromaeosaurs are shown, all covered with feathers. Microraptor gui (flying), Velociraptor mongoliensis, Austroraptor cabazai, Dromaeosaurus albertensis, Utahraptor ostrommaysorum, Deinonychus antirrhopus. A human is shown on the left. Most of the dinosaurs are bigger than the human.
Size of Utahraptor (5) compared with other dromaeosaurs and a human. It is the biggest one in the picture. The picture is from here. Fred Wierum, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons.

Terror Birds and Other Giant Birds

After the Cretaceous-Paleogene extinction event 66 million years ago birds continued evolving. Some of them became large standing 1 – 3 meters (3-10 feet) and weighing hundreds or even thousands of pounds. From about 53 million years ago until 100,000 years ago there were large birds that we refer to as Terror Birds. They lived at the same time as humans. However, there were other large and scary birds. Dromornis stirtoni was a flightless bird that lived 7-8 million years ago, it was over three meters in height (10 feet) and weighed 500-600 kilograms (1,100 to 1,300 pounds). Below are some illustrations.

pencil drawing, digital coloring of Paraphysornis brasiliensis, a Terror Bird. | Birds are Avian Dinosaurs
Paraphysornis brasiliensis, a Terror Bird, 8 feet tall weighing 400–530 pounds, this is a terror bird from the Early Miocene of Brazil,: Snowmanradio (talk)Paraphysornis_BW.jpg:  Nobu Tamura (http://spinops.blogspot.com), CC BY 3.0 <https://creativecommons.org/licenses/by/3.0&gt;, via Wikimedia Commons.
The Kelenken, Devincenzia, Phorusrhacos, and Titanis birds are all larger than the human standing on the left hand side. Kelenken guillermoi is the largest.
Size comparison of some phorusrhacids (Terror Birds), including Kelenken, Devincenzia, Phorusrhacos, and Titanis. Picture taken from here. PaleoNeolitic, CC BY 4.0 <https://creativecommons.org/licenses/by/4.0&gt;, via Wikimedia Commons.
A flightless bird with huge yellow beak. | Birds are Avian Dinosaurs
A pencil-drawn reconstruction of Dromornis stirtoni. Picture is taken from here. Nobu Tamura (http://spinops.blogspot.de), CC BY-SA 3.0 http://creativecommons.org/licenses/by-sa/3.0/, via Wikimedia Commons