Both species of anoa have been classified as endangered since the 1960s, and the population continues to decrease.

Both species will kill each other's pups, given the opportunity.

Both the number of base pairs and the number of genes vary widely from one species to another, and there is only a rough correlation between the two ( an observation known as the C-value paradox ).

Both species are smaller than the spotted hyena but larger than the aardwolf.

Both males and females grow to an adult length of to from snout to vent, with a total length of to making it the third largest aquatic salamander species in the world ( next to the Chinese giant salamander and the Japanese giant salamander ) and the largest in North America.

Both species, C. a. alleganiensis and C. a. bishopi undergo a metamorphosis after around a year and a half of life.

Both species have much grey in their wings in males, which does not occur in the Common Kestrel or its close living relatives but does in almost all other falcons.

Both species had their genomes sequenced and they appear to have diverged around 400, 000 years ago.

Both orangutan species are considered to be Endangered with the Sumatran orangutan being Critically Endangered.

Both species have very long ( approximately 35 centimetres ), flexible, blue tongues that they use to strip leaves and buds from trees.

Both size classes lived along side each other, and while researchers had previously suggested that they represent different species, Christopher Bennett showed that the differences between them are consistent with the concept that they represent females and males, and that Pteranodon species were sexually dimorphic.

Both species show extreme sexual dimorphism, possibly the largest of any mammal, with southern males typically five to six times heavier than the females.

Both species became extinct before the last glaciation.

Both species were larger than the modern hippopotamus, averaging about 1 meter ( 3. 3 feet ) longer.

* Both codes consider the first part of the two-part name for a species to be the " genus name ".

Both subgenus Magnolia and subgenus Yulania include species of major horticultural importance, and a change of name would be very undesirable for many people, especially in the horticultural branch.

Both species and hybrid rhododendrons ( including azaleas ) are used extensively as ornamental plants in landscaping in many parts of the world, and many species and cultivars are grown commercially for the nursery trade.

Both oviparous and ovoviviparous, as well as genuinely viviparous, species exist, although the Peripatopsidae essentially lack a placenta.

Both are typified by many grass species.

Both species are coded as thin wispy cirrus ( C < sub > H </ sub > 1 ).

Both species can grow to 3 ft 6 in ( 1. 07 m ) and can weigh up to 46 lb ( 21 kg ).

Both these species occur in a normal, a black and a rare white morph, confirming the view that simply dividing into species based on morph ( as had been done earlier ) is incorrect.

Both males are females will incubate, with the male often incubating at night and, during the day, defending the nest territory during the day while the female incubates.

Both parents will incubate a brood for 23 – 24 days, and the precocial young leave the nest shortly after hatching.

Both Great and Lesser Frigatebirds used to nest on the island but have subsequently become extinct as breeders, though they continue to use the island for roosting.

Both parents share the care of the nest.

Both of these were common, but have suffered from loss of habitat, from competition for nest sites with introduced House Sparrows ( Passer domesticus ), and nest-predation by European Starlings ( Sturnus vulgaris ) and Great Kiskadees ( Pitangus sulphuratus )-this last species was deliberately introduced as late as 1957, with the intent that it would control the previously introduced anoles.

Both of these birds nest in the Edwards Plateau, the Warbler exclusively.

Both the Mountain Bluebird and the Western Bluebird nest in Bickleton.

Both parents build the nest, sit on the egg or eggs, and feed the young.

Both members of the pair help to build the nest, incubate the eggs ( generally two per clutch ) and feed the hatched young.

Both sexes build the nest, which is a shallow scrape ( or occasionally a platform of mud and vegetation ) lined with vegetation and sometimes a few feathers, and placed within a half-metre ( 18 in ) of the edge of a small pond.

Both parents feed the young at the nest by regurgitating food.

Both birds build the nest on a main fork or a limb high in a tree, 12-20m high made of dead twigs and lined with grass or other vegetation and sheep ’ s wool.

Both the male and female take part in nest building, incubation and care of chicks.

Both parents take part in nest building and feeding but it is suggested that only the female incubates.

Both birds gather nest materials, but the female does most of the construction, usually on a horizontal limb or in a crotch well away from the tree trunk, at any height.

Both feed the young, often leaving them alone for long times ; this unusual habit for wading birds may be made possible by the thick nest walls.

Both the male and female visit the nest site for almost half a year before egg laying takes place.

Both birds build the nest on floating platform, after clearing out an area of approximately across.

Both the nest and platform are made of aquatic vegetation.

Both parents build the nest and feed the young.

Both sexes gather nesting material and build the nest, but the division of labour isn't always exactly equal.

Both sexes build the nest and rear the young, though only the female broods them.

Both the male and female take part in nest building.

Both sexes cooperate in building a nest in the earth, but only the male incubates the eggs and tends the young.