We live in a world full of inconsistencies, and the enormous variations in the size of living organisms may be the strangest among them all. Some animals weigh thousands of kilograms, while others have a length of less than a millimeter. The largest and smallest species we know to be living on Earth at the moment are presented hereunder.
Bird
Currently, the ostrich is the largest known bird on Earth; it weighs about 150 kilograms and can exceed 180 cm in height (6 feet). It flies at 70 kilometers per hour, which makes it the fastest creature. The ostrich also lives and feeds on fruits, nuts, and small insects in groups of ten to fifteen.
The smallest bird known to date is the hummingbird; its weight does not exceed two grams and its height at puberty is around six centimeters. This bird lives and feeds on small flowers in Cuba, and its female lays eggs as small as the size of a coin in a nest.
Insects
The biggest known living insect is the rhinoceros beetle; its length reaches 12.5 cm and its width is 4 cm. In the Amazon rainforest, these insects live and have a sturdy shell that covers them, so they have almost no predators.
It is a fairy wasp with an average length of less than 1 mm, as far as the smallest insect is concerned. There are large species of this insect, the smallest of which is the female kikiki, about 0.15 mm long. The majority of fairy wasps live in the state of Hawaii, but scientists have discovered new species in Costa Rica in the last decade.
Reptiles
The komodo dragon lizard is the largest known living reptile of our time; it is up to 136 kilograms in height and more than three meters in height. This lizard inhabits some Indonesian islands and is distinguished by its terrifying presence, which is the reason why it is called a dragon, resembling the monsters of ancient myths.
The predator komodo dragon lizard feeds on smaller species, including deer, pigs, and buffaloes. It can also eat carrion and hunting its prey relies on trickery.
The garagua lizard, which lives near the coast of the Dominican Republic on an island in the Caribbean Sea, is the smallest known living reptile; it is considered by some scientists to be one of the smallest animals, including mammals and birds.
The adult male is around 1.6 cm long and feeds on small-tree plants and leaves; however, due to extensive logging, these species are endangered.
Spiders
The largest known spider on Earth today is the bird-eating spider; its leg length exceeds 30 cm and it weighs up to 170 grams. The bird-eating spider lives for a long time; the male spider's average age ranges from 3-6 years, while the lifespan of the female can extend up to 20 years.
Small birds and insects feed on this spider; that is why it is called a bird eater. It is not poisonous despite its frightening appearance; however, it can be dangerous due to its sharp claws and can inflict wounds. Bato Dejo, which is approximately 0.37 mm long and lives in Colombia, is the smallest known spider.
The Largest and Smallest Living Organisms
The largest known organism is now considered to be the blue whale; it is about 30 meters long and can weigh up to 200 tons. The weight of its tongue alone corresponds to the weight of an elephant. Almost 4 tons of krill, shrimp-like arthropods, are consumed daily by the adult blue whale.
The blue whale swims at a speed that reaches 5 miles per hour, alone or in small groups, but its speed can reach 30 miles per hour. Except in the Arctic, it lives in all the oceans. The blue whale lives for 80 to 90 years as well, but can live up to 110 years as well.
The smallest species ever are very difficult to classify, as scientists every day discover new tiny creatures.